[Enhancement] add name_prefix argument to aws_elasticache_parameter_group

[tabito-hara]

Description

• The name_prefix attribute has been implemented for the aws_elasticache_parameter_group resource.
• Implemented in the same manner as previous PRs (e.g., Add name_prefix support for WAFv2 rule groups #33206) that added name_prefix support for other resources.
• The name attribute is now optional. If neither name nor name_prefix is specified, a random suffix with the prefix terraform- is generated.
• While the AWS API documentation does not specify this, the AWS Management Console indicates that the maximum length of parameter group names is 255. Name length validation has been implemented accordingly.
• Added acctests to confirm:
  • When name_prefix is specified, the parameter group name is generated as name_prefix + UniqueIdSuffix.
  • When neither name nor name_prefix is specified, the parameter group name is generated as terraform- + UniqueIdSuffix.

Verification

• When running the newly added acctest TestAccElastiCacheParameterGroup_namePrefix, CloudTrail logs confirm that the CreateParameterGroup action was called with the request parameter cacheParameterGroupName set to "tf-acc-test-511342620309676706420250314160149600000000001".
• When running the newly added acctest TestAccElastiCacheParameterGroup_nameGenerated, CloudTrail logs confirm that the CreateParameterGroup action was called with the request parameter cacheParameterGroupName set to "terraform-20250314153805770600000001".
• Both results match the expected behavior.
• The existing acctests confirm that the modifications in this PR do not affect the current behavior.

Relations

Closes #41845

References

Output from Acceptance Testing

$ make testacc TESTS='TestAccElastiCacheParameterGroup_' PKG=elasticache
make: Verifying source code with gofmt...
==> Checking that code complies with gofmt requirements...
make: Running acceptance tests on branch: 🌿 f-aws_elasticache_parameter_group-add_name_prefix 🌿...
TF_ACC=1 go1.25.5 test ./internal/service/elasticache/... -v -count 1 -parallel 20 -run='TestAccElastiCacheParameterGroup_'  -timeout 360m -vet=off
2026/01/09 21:59:08 Creating Terraform AWS Provider (SDKv2-style)...
2026/01/09 21:59:08 Initializing Terraform AWS Provider (SDKv2-style)...
=== RUN   TestAccElastiCacheParameterGroup_Redis_basic
=== PAUSE TestAccElastiCacheParameterGroup_Redis_basic
=== RUN   TestAccElastiCacheParameterGroup_Valkey_basic
=== PAUSE TestAccElastiCacheParameterGroup_Valkey_basic
=== RUN   TestAccElastiCacheParameterGroup_disappears
=== PAUSE TestAccElastiCacheParameterGroup_disappears
=== RUN   TestAccElastiCacheParameterGroup_addParameter
=== PAUSE TestAccElastiCacheParameterGroup_addParameter
=== RUN   TestAccElastiCacheParameterGroup_removeAllParameters
=== PAUSE TestAccElastiCacheParameterGroup_removeAllParameters
=== RUN   TestAccElastiCacheParameterGroup_RemoveReservedMemoryParameter_allParameters
=== PAUSE TestAccElastiCacheParameterGroup_RemoveReservedMemoryParameter_allParameters
=== RUN   TestAccElastiCacheParameterGroup_RemoveReservedMemoryParameter_remainingParameters
=== PAUSE TestAccElastiCacheParameterGroup_RemoveReservedMemoryParameter_remainingParameters
=== RUN   TestAccElastiCacheParameterGroup_switchReservedMemoryParameter
=== PAUSE TestAccElastiCacheParameterGroup_switchReservedMemoryParameter
=== RUN   TestAccElastiCacheParameterGroup_updateReservedMemoryParameter
=== PAUSE TestAccElastiCacheParameterGroup_updateReservedMemoryParameter
=== RUN   TestAccElastiCacheParameterGroup_uppercaseName
=== PAUSE TestAccElastiCacheParameterGroup_uppercaseName
=== RUN   TestAccElastiCacheParameterGroup_description
=== PAUSE TestAccElastiCacheParameterGroup_description
=== RUN   TestAccElastiCacheParameterGroup_namePrefix
=== PAUSE TestAccElastiCacheParameterGroup_namePrefix
=== RUN   TestAccElastiCacheParameterGroup_nameGenerated
=== PAUSE TestAccElastiCacheParameterGroup_nameGenerated
=== RUN   TestAccElastiCacheParameterGroup_tags
=== PAUSE TestAccElastiCacheParameterGroup_tags
=== CONT  TestAccElastiCacheParameterGroup_Redis_basic
=== CONT  TestAccElastiCacheParameterGroup_switchReservedMemoryParameter
=== CONT  TestAccElastiCacheParameterGroup_updateReservedMemoryParameter
=== CONT  TestAccElastiCacheParameterGroup_removeAllParameters
=== CONT  TestAccElastiCacheParameterGroup_RemoveReservedMemoryParameter_remainingParameters
=== CONT  TestAccElastiCacheParameterGroup_RemoveReservedMemoryParameter_allParameters
=== CONT  TestAccElastiCacheParameterGroup_Valkey_basic
=== CONT  TestAccElastiCacheParameterGroup_addParameter
=== CONT  TestAccElastiCacheParameterGroup_namePrefix
=== CONT  TestAccElastiCacheParameterGroup_tags
=== CONT  TestAccElastiCacheParameterGroup_disappears
=== CONT  TestAccElastiCacheParameterGroup_nameGenerated
=== CONT  TestAccElastiCacheParameterGroup_uppercaseName
=== CONT  TestAccElastiCacheParameterGroup_description
--- PASS: TestAccElastiCacheParameterGroup_disappears (43.39s)
--- PASS: TestAccElastiCacheParameterGroup_namePrefix (43.44s)
--- PASS: TestAccElastiCacheParameterGroup_nameGenerated (44.10s)
--- PASS: TestAccElastiCacheParameterGroup_description (45.92s)
--- PASS: TestAccElastiCacheParameterGroup_uppercaseName (48.66s)
--- PASS: TestAccElastiCacheParameterGroup_Redis_basic (48.66s)
--- PASS: TestAccElastiCacheParameterGroup_Valkey_basic (48.70s)
--- PASS: TestAccElastiCacheParameterGroup_removeAllParameters (60.39s)
--- PASS: TestAccElastiCacheParameterGroup_addParameter (64.25s)
--- PASS: TestAccElastiCacheParameterGroup_updateReservedMemoryParameter (65.56s)
--- PASS: TestAccElastiCacheParameterGroup_RemoveReservedMemoryParameter_allParameters (65.57s)
--- PASS: TestAccElastiCacheParameterGroup_switchReservedMemoryParameter (66.23s)
--- PASS: TestAccElastiCacheParameterGroup_RemoveReservedMemoryParameter_remainingParameters (66.76s)
--- PASS: TestAccElastiCacheParameterGroup_tags (77.02s)
PASS
ok      github.com/hashicorp/terraform-provider-aws/internal/service/elasticache        81.001s

[github-actions]

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[tabito-hara]

Rebase onto the latest main branch and replace interface{} with any to align with the modernization of Go code.

[ksudana]

@tabito-hara is this still open?

[tabito-hara]

@ksudana

Thank you for your comment.
This PR is still open.

I will rebase this on the latest main branch and resolve conflicts.

[ksudana]

Thanks @tabito-hara, if we can get this change in it will be very helpful

[tabito-hara]

Rebased on the latest branch , resolving conflicts.
Reran the acceptance tests.