Simplify CI merge queue logic #11331

Is your feature request related to a problem or challenge?

#11097 introduced merge queues. This issue is for some potential followup work to see if we can simplify things, where possible.

Describe the solution you'd like

Things to look into:

• Is there a way to achieve the python script logic in a simpler way, possibly without needing python scripts at all?
  • Related to triggering only the necessary suites
• Try to centralize the dispatch logic: currently the logic for triggering a suite is located within paths.yaml, ci.yml as well as the python scripts (e.g. for miri) which is confusing, can we try put it in a single location?
• Reconsider need for the cache-refresh-only logic; how much do we gain from these caches, does it make the complexity in our CI code worth it?

Describe alternatives you've considered

No response

Additional context

See discussion in original PR for more context as to some of these points