[#9082] fix(core): validate job run id parsing to avoid SIOOBE

[HaJunYoo]

What changes were proposed in this pull request?

• Route job ID parsing in JobMetaService#getJobByIdentifier/deleteJob through parseJobRunId so malformed IDs throw NoSuchEntityException instead of runtime errors.
• Fix the missing-job error message to include the actual identifier (ident.toString()).
• Keep DB-backed tests as @TestTemplate so BackendTestExtension can inject the relational backend per invocation (required for H2/MySQL/PostgreSQL runs).

Why are the changes needed?

• Prevents StringIndexOutOfBoundsException/NumberFormatException from malformed job IDs and ensures callers get a consistent NoSuchEntityException.
• The backend-injection extension only runs with @TestTemplate; using plain @Test would bypass it and leave the backend uninitialized.

Fix: #9082

Does this PR introduce any user-facing change?

• No API or behavior changes. Malformed job IDs now consistently return NoSuchEntityException instead of unexpected runtime errors, improving error consistency.

How was this patch tested?

• Added unit tests:
  • TestJobMetaService#testGetJobWithMalformedIdentifierThrowsNoSuchEntityException
  • TestJobMetaService#testDeleteJobWithMalformedIdentifierThrowsNoSuchEntityException
• Formatting: ./gradlew :core:spotlessJavaCheck
• Unit: ./gradlew :core:test --tests "org.apache.gravitino.storage.relational.service.TestJobMetaService"