Add resource metric integration test

[varunch77]

Description of the issue

There is no integration test that verifies that an entity is being sent when we send resource metrics such as cpu and memory to CloudWatch—this is currently a gap in our testing.

Description of changes

• Create an agent config to send resource metrics to Cloudwatch
• Sign and send a request that calls ListEntitiesForMetric to get the entity associated with our metrics
• Validate the returned entity
• Update our integration testing IAM role to include permission for ListEntitiesForMetric

License

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Tests

Integration test run: https://github.com/aws/amazon-cloudwatch-agent/actions/runs/12838570212

[varunch77]

Changes:

• Removed anything logs-related
• Moved the location of the test into the entity folder
• Created a helper function in the util/common/metrics package to handle building the ListEntitiesForMetric call
• Updated the entity validation to use existing helper functions

[zhihonl]

Can you attach a new integration test run with this change so we can make sure the test still passes?

[varunch77]

• Moved test into the metric_value_benchmark suite of tests and restructured as needed
• New integration test run: https://github.com/aws/amazon-cloudwatch-agent/actions/runs/12994059613
• Example of EntityMetrics test passing: https://github.com/aws/amazon-cloudwatch-agent/actions/runs/12994059613/job/36237893873#step:8:4090
• I went through the failing metric_value_benchmark tests and verified that they were failing for other reasons