Fix flaky test AzureBlobStoreRepositoryTests

[sachinpkale]

Description

• Due to the default SUITE scope on AzureBlobStoreRepositoryTests, the number of documents indexed with each test gets added and huge number of documents and segments created as part of this takes time for snapshot to create and eventually times out the test suite.
• We can reproduce this issue with following:

/gradlew ':plugins:repository-azure:internalClusterTest' --tests "org.opensearch.repositories.azure.AzureBlobStoreRepositoryTests"  -Dtests.seed=773F78819373DA07

• As part of this PR, we change the scope to TEST.

Related Issues

• [AUTOCUT] Gradle Check Flaky Test Report for AzureBlobStoreRepositoryTests #14291

Check List

• Functionality includes testing.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

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[github-actions]

❌ Gradle check result for a3af3b9: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❌ Gradle check result for 8189f5e: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❕ Gradle check result for 8189f5e: UNSTABLE

Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.47%. Comparing base (1628152) to head (8189f5e).
Report is 24 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #17905      +/-   ##
============================================
+ Coverage     72.43%   72.47%   +0.03%     
- Complexity    66789    66790       +1     
============================================
  Files          5449     5452       +3     
  Lines        309085   309210     +125     
  Branches      44979    44991      +12     
============================================
+ Hits         223899   224085     +186     
+ Misses        66906    66767     -139     
- Partials      18280    18358      +78     

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