[Cloud Security] Fix flaky metering tests

[CohenIdo]

Solves:

• Failing test: Serverless Security API Integration Tests.x-pack/test_serverless/api_integration/test_suites/security/cloud_security_posture/serverless_metering/cloud_security_metering·ts - Serverless security API cloud_security_posture Intercept the usage API request sent by the metering background task manager Should intercept usage API request with all integrations usage records #188660
• Failing test: Serverless Security API Integration Tests.x-pack/test_serverless/api_integration/test_suites/security/cloud_security_posture/serverless_metering/cloud_security_metering·ts - Serverless security API cloud_security_posture Intercept the usage API request sent by the metering background task manager Should intercept usage API request for CSPM #188829

Summary

The error logs indicate that while we index N documents, the metering API intercepts only N-X documents. Previously, to address a similar issue, we switched to bulk indexing to ensure all test-related documents were indexed before tests began.

Although this adjustment resolved the problem in some flaky test runs, we still encountered intermittent failures in one of the hundreds runs.

Upon further investigation, I found that even with bulk indexing, there are rare cases where tests start before all relevant documents have finished indexing. I confirmed this by increasing the number of documents from 5 to 150, which made the error appear more consistently.

To address this, I updated the test logic to retry the expect assertion, reducing the likelihood of these occasional failures.

[elasticmachine]

Pinging @elastic/kibana-cloud-security-posture (Team:Cloud Security)

[kibanamachine]

Flaky Test Runner Stats

🎉 All tests passed! - kibana-flaky-test-suite-runner#7276

[✅] x-pack/test_serverless/api_integration/test_suites/security/config.ts: 50/50 tests passed.

see run history

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: cf39df3

Metrics [docs]

✅ unchanged