Fix flaky testClusterStateBatchedUpdates test

[amkhar]

Description

Move the assertion to more deterministic test where cluster state update will happen for sure. Executed the test 1000 time locally in a loop to verify it's not going to be flaky anymore.

Related Issues

Resolves #10899

Check List

• New functionality includes testing.
• All tests pass
  - [x] New functionality has been documented.
  - [x] New functionality has javadoc added
• Failing checks are inspected and point to the corresponding known issue(s) (See: Troubleshooting Failing Builds)
• Commits are signed per the DCO using --signoff
  - [x] Commit changes are listed out in CHANGELOG.md file (See: Changelog)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[ashking94]

LGTM.

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: SUCCESS ✅
• URL: https://build.ci.opensearch.org/job/gradle-check/28999/
• CommitID: afc5919

[codecov]

Codecov Report

Merging #10922 (afc5919) into main (5a288ed) will decrease coverage by 0.08%.
Report is 9 commits behind head on main.
The diff coverage is 53.66%.

@@             Coverage Diff              @@
##               main   #10922      +/-   ##
============================================
- Coverage     71.22%   71.15%   -0.08%     
- Complexity    58678    58682       +4     
============================================
  Files          4869     4872       +3     
  Lines        276496   276682     +186     
  Branches      40203    40219      +16     
============================================
- Hits         196936   196860      -76     
- Misses        63114    63440     +326     
+ Partials      16446    16382      -64     

Files	Coverage Δ
...search/repositories/s3/AmazonAsyncS3Reference.java	84.61% <100.00%> (+1.28%)	⬆️
.../repositories/s3/AmazonAsyncS3WithCredentials.java	100.00% <100.00%> (ø)
...org/opensearch/repositories/s3/S3AsyncService.java	72.28% <100.00%> (+1.09%)	⬆️
...va/org/opensearch/repositories/s3/S3BlobStore.java	68.75% <100.00%> (+0.49%)	⬆️
...a/org/opensearch/repositories/s3/S3Repository.java	70.08% <100.00%> (+0.25%)	⬆️
...search/cluster/coordination/CoordinationState.java	88.39% <ø> (ø)
.../org/opensearch/cluster/service/MasterService.java	83.72% <100.00%> (-1.34%)	⬇️
...h/common/blobstore/stream/write/WritePriority.java	100.00% <100.00%> (ø)
...nsearch/gateway/remote/RemotePersistenceStats.java	100.00% <100.00%> (ø)
...epositories/blobstore/ChecksumBlobStoreFormat.java	95.45% <100.00%> (+0.29%)	⬆️
... and 12 more

... and 458 files with indirect coverage changes

[github-actions]

Compatibility status:

Checks if related components are compatible with change afc5919

Incompatible components

Incompatible components: [https://github.com/opensearch-project/cross-cluster-replication.git, https://github.com/opensearch-project/performance-analyzer.git]

Skipped components

Compatible components

Compatible components: [https://github.com/opensearch-project/security.git, https://github.com/opensearch-project/alerting.git, https://github.com/opensearch-project/index-management.git, https://github.com/opensearch-project/anomaly-detection.git, https://github.com/opensearch-project/job-scheduler.git, https://github.com/opensearch-project/sql.git, https://github.com/opensearch-project/asynchronous-search.git, https://github.com/opensearch-project/common-utils.git, https://github.com/opensearch-project/observability.git, https://github.com/opensearch-project/k-nn.git, https://github.com/opensearch-project/reporting.git, https://github.com/opensearch-project/security-analytics.git, https://github.com/opensearch-project/custom-codecs.git, https://github.com/opensearch-project/opensearch-oci-object-storage.git, https://github.com/opensearch-project/performance-analyzer-rca.git, https://github.com/opensearch-project/ml-commons.git, https://github.com/opensearch-project/geospatial.git, https://github.com/opensearch-project/notifications.git, https://github.com/opensearch-project/neural-search.git]

[amkhar]

@shwetathareja @Bukhtawar

[ashking94]

@amkhar can you strike out things from checklist that don't apply for the build checklist to be green.

[Bukhtawar]

Code coverage checks are failing, might need to be addressed

[amkhar]

Code coverage checks are failing, might need to be addressed

Thanks @Bukhtawar for approval. This PR is just for test change no code changes are part of this PR.

[mch2]

Going ahead with this as its blocking a lot of checks and gc passes.