CI - iOS uncached times out / caches stored on PRs

[mikehardy]

This is a CI optimization - but I just noticed two things:

• caches that really should be available all the time (things like, ccache on main) are being evicted, likely because PRs are storing caches for things that should only be stored on main
• uncached runs of iOS e2e workflow are timing out (see above - compile takes increasingly longer for firebase-ios-sdk - probably +15mins to fix)

[github-actions]

Hello 👋, to help manage issues we automatically close stale issues.

This issue has been automatically marked as stale because it has not had activity for quite some time.Has this issue been fixed, or does it still require attention?

This issue will be closed in 15 days if no further activity occurs.

Thank you for your contributions.

[mikehardy]

still needs a look

[github-actions]

Hello 👋, to help manage issues we automatically close stale issues.

This issue has been automatically marked as stale because it has not had activity for quite some time.Has this issue been fixed, or does it still require attention?

This issue will be closed in 15 days if no further activity occurs.

Thank you for your contributions.