[Admin] Refresh featured orgs

### Describe the problem

This list of featured organizations is outdated. Some events are already over while new organizations that would qualify to be displayed here, aren't.

https://github.com/hackclub/hcb/blob/37550a214c98bf37d9eb3b1a0c75aa18ef7c029d/app/controllers/static_pages_controller.rb#L24-L30

### Describe the feature/solution (optional)

Remove inactive organizations from the list and add some new organizations in their place.

Open app/controllers/static_pages_controller.rb around lines 24-30 and inspect how featured organizations are listed. Check which listed organizations are inactive and identify suitable replacements, then update the list so it contains current qualifying organizations and verify the featured section renders correctly.

Written by the indexing model from the issue text.