[ELB]: opentelekomcloud_lb_member_v3 zero weight fix

[artem-lifshits]

Summary of the Pull Request

Fix resource creation for zero weight value.

PR Checklist

• Refers to: Lb_member_v3 can not be created with weight set to 0 via Terraform #2431
• Tests added/passed.
• Release notes added.

Acceptance Steps Performed

=== RUN   TestLBMemberV3_basic
=== PAUSE TestLBMemberV3_basic
=== CONT  TestLBMemberV3_basic
--- PASS: TestLBMemberV3_basic (49.24s)
=== RUN   TestLBMemberV3_ZeroWeight
=== PAUSE TestLBMemberV3_ZeroWeight
=== CONT  TestLBMemberV3_ZeroWeight
--- PASS: TestLBMemberV3_ZeroWeight (48.01s)
=== RUN   TestLBMemberV3_import
=== PAUSE TestLBMemberV3_import
=== CONT  TestLBMemberV3_import
--- PASS: TestLBMemberV3_import (34.82s)
PASS

Process finished with the exit code 0

[otc-zuul]

Build succeeded.
https://zuul.otc-service.com/t/eco/buildset/9ea5b929f9384a4cbf4d13a4cd4b200f

✔️ build-otc-releasenotes SUCCESS in 5m 36s
✔️ noop SUCCESS in 0s
✔️ otc-golangci-lint SUCCESS in 2m 59s
✔️ golang-make-test SUCCESS in 4m 23s
✔️ golang-make-vet SUCCESS in 3m 28s
✔️ tflint SUCCESS in 1m 58s
✔️ goreleaser-build SUCCESS in 8m 12s
✔️ otc-terraform-visualize-main SUCCESS in 6m 20s