Dont run (mobile) github actions (for required checks) if there is no need

[phlax]

In #24407 a change was made to not use the paths feature in github actions to exclude checks

this was done to ensure that the checks could be required for PRs to pass

the problem with this approach is that it pulls a full copy of the repo and is much slower than using githubs paths (which afaict uses its own diff algorithm against the target branch, and perhaps pre-checksout the repo - not sure about this exactly)

in more recent version of the github actions/checkout action the default is to pull the repo with a depth of 1, so the current mobile/should_run_ci.sh script, where it assumes that the full repo is checked out, breaks (this is easy enough to workaround but just hightlights the issue)

i think we can speed this up and reduce the load on CI considerably by reverting to using the paths selector and adding the github way of allowing a required check to pass when skipped (https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/defining-the-mergeability-of-pull-requests/troubleshooting-required-status-checks#handling-skipped-but-required-checks)

like the azp way its a bit kludgy but it think it would be quite a bit faster/more efficient

[phlax]

cc @jpsim @alyssawilk

i was going to comment something similar on the PR but it landed before i had gotten round to reviewing it

[jpsim]

i think we can speed this up and reduce the load on CI considerably by reverting to using the paths selector and adding the github way of allowing a required check to pass when skipped (https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/defining-the-mergeability-of-pull-requests/troubleshooting-required-status-checks#handling-skipped-but-required-checks)

Oh nice, I wasn't aware that this was possible.

[github-actions]

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[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or "no stalebot" or other activity occurs. Thank you for your contributions.