Fix data source picker for alerts card

[jowg-amazon]

Description

• Fixes the data source picker for the alerts card so it loads alerts from different selected clusters
• Loads the default cluster by default

https://github.com/user-attachments/assets/ef0bab87-77b3-4a55-8547-e9fafa1ed288

Issues Resolved

[List any issues this PR will resolve]

Check List

• [ ] New functionality includes testing.
  • [ ] All tests pass
• [ ] New functionality has been documented.
  • [ ] New functionality has javadoc added
• [ ] Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license. For more information on following Developer Certificate of Origin and signing off your commits, please check here.