fix(PVO11Y-4961): Change group by to include source cluster

[martysp21]

Description

I need source cluster to be included for the alert usability.

Pre-Submission Checklist

• Jira Ticket: If a corresponding Jira ticket exists, it is linked in the description above, in the PR name, and/or in the commit message.
• Alert Tests: New or modified alerts include tests to ensure they function correctly.
• SOP / Runbook: Any required SOP has been created or updated as needed. If it has direct connection to the dashboard or alert - It should be included within the dashboard or alert's runbook label respectively.
• Dashboards Addition: New dashboards or significant changes to them should have a link to the staging instance for validation purposes.
• Contribution Guides: This submission follows the guidelines in our CONTRIBUTING.md - specifically about the commit conventions and PR instructions - together with our README.md which explains contents of this repository with useful examples for contribution.
• Pipeline Finished Successfully

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Deployment Notice

• Production Deployment: For any changes to alerts, recording rules or dashboards, I understand that the deployment of changes to production requires updating the commit reference to o11y in app-interface repository.

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Review

Once your PR is ready please let us know in the #forum-konflux-o11y slack channel. Tag @konflux-o11y-ic for assistance.

[martysp21]

/retest

[pacho-rh]

Made this change as part of https://github.com/redhat-appstudio/o11y/pull/867/files#diff-2229f18913c457accaf8f559473a677a70d2cba7fb36311613eb78c0a63e5602R39

It did not include the added recording rules testing you have here though.