Fix testIndexDeletionDuringSnapshotCreationInQueue flaky test

[dreamer-89]

Description

Test testIndexDeletionDuringSnapshotCreationInQueue creates a async snapshot (wait_for_completion=false) which conflicts during test clean up where repository is deleted. The conflict happens due to in progress snapshot. The fix here is to wait for snapshot to be in completed state.

Related Issues

Resolves #5031

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • 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
• Commit changes are listed out in CHANGELOG.md file (See: Changelog)
• Public documentation issue/PR created

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[github-actions]

Compatibility status:

Checks if related components are compatible with change 2e6c3c6

Incompatible components

Skipped components

Compatible components

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

[github-actions]

❕ Gradle check result for 2e6c3c6: UNSTABLE

• TEST FAILURES:

      1 org.opensearch.search.SearchWeightedRoutingIT.testMultiGetWithNetworkDisruption_FailOpenEnabled

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