[9.2] (backport #11499) fix(tests): use assert.CollectT in TestContainerCMDAgentMonitoringRuntimeExperimental

[mergify]

What does this PR do?

Updates TestContainerCMDAgentMonitoringRuntimeExperimental to use the assert.CollectT instead of the testing.T inside require.EventuallyWithT.

Why is it important?

Prevents the code from failing on the first pass of require.EventuallyWithT. Now it retries transient assertion errors up to the timeout.

Checklist

• I have read and understood the pull request guidelines of this project.
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test

Related issues

• For [Flaky Test]: TestContainerCMDAgentMonitoringRuntimeExperimental and TestContainerCMDAgentMonitoringRuntimeExperimentalPolicy– expected correct runtime name for monitoring component #11162.

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This is an automatic backport of pull request #11499 done by [Mergify](https://mergify.com).

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 17e6e04

Failed CI Steps

• Win2022:sudo:default
• Win2025:sudo:default

cc @mauri870