Update prometheus-eks.yaml to include cluster_name and region_name

[soumyabavirisetti]

The "cluster_name" and "region_name" not specified in the prometheus-eks.yaml. So if customers use this yaml, they'll face the below error :

2025/02/03 11:00:06 E! Failed to generate TOML configuration validation content: [Under path : /agent/ruleRegion/ | Error : Region info is missing for mode: onPrem Under path : /logs/metrics_collected/prometheus/ | Error : ClusterName is not defined] 2025/02/03 11:00:06 Under path : /agent/ruleRegion/ | Error : Region info is missing for mode: onPrem 2025/02/03 11:00:06 Under path : /logs/metrics_collected/prometheus/ | Error : ClusterName is not defined 

Description of the issue

Describe the problem or feature in addition to a link to the issues.

Description of changes

How does this change address the problem?

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

Describe what tests you have done.

Requirements

Before committing the code, please verify the following:

• If this commit includes changes to existing sample configurations, you acknowledge that you have confirmed this will not impact existing customer behavior.
• If not necessary, consider creating a new sample configuration for this change.