In flutter/packages@df0f423 we fixed an issue where dart format wasn't reliably doing the right thing (especially in CI) because pub get needs to be run to make sure the min Dart SDK version is detected correctly by dart format. Unfortunately there is an edge case where it still does the wrong thing, which is sub-packages other than example (example is handled automatically by pub get); in pigeon for instance we're currently enforcing 3.7 in CI because that's what the main package uses, but the platform_test sub-packages are set to 3.9. This causes issues for anyone who has actually built the platform tests locally since that change.

We need the repo tooling to run pub get in all subpackages of the package (ignoring example/ directories), not just at the top level.