[flutter_tools] exec rather than spawn subprocess from bin/internal/shared.sh by @christopherfujino in https://github.com/flutter/flutter/pull/99871

Add portForwarder for ProxiedDevice. by @chingjun in https://github.com/flutter/flutter/pull/100111

Add more specific cause on web development tool error output by @yuseok in https://github.com/flutter/flutter/pull/98553

MigrateConfig and migrate integration testing base by @GaryQian in https://github.com/flutter/flutter/pull/99092

[macOS] Enable universal binary builds by default by @cbracken in https://github.com/flutter/flutter/pull/100271

[flutter_tools] Null safe update packages by @christopherfujino in https://github.com/flutter/flutter/pull/99357