Don't limit CI concurrency on main

[agners]

Proposed change

The CI workflow used a blanket cancel-in-progress: true, which makes sense for PR runs (collapse to the latest commit) but means pushes to main cancel each other when several PRs merge in quick succession. There is no shared state between CI runs that would justify either cancelling or serializing them — each run is independent — and we'd rather see every commit on main get a full check.

Make the concurrency group unique per run_id for non-PR events so pushes to main neither cancel nor queue, while PRs keep the existing cancel-on-new-push behavior through the shared per-ref group.

This mirrors the spirit of #6782, which addressed the same blanket cancellation in the builder workflow (though there the fix was to queue rather than run in parallel, since the builder publishes wheels).

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (which adds functionality to the supervisor)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:
• Link to cli pull request:
• Link to client library pull request:

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Ruff (ruff format supervisor tests)
• Tests have been added to verify that the new code works.

If API endpoints or add-on configuration are added/changed:

• Documentation added/updated for developers.home-assistant.io
• CLI updated (if necessary)
• Client library updated (if necessary)