* Removes retries from "pub get" and proxies its stdout output

* Fix issue where ErrorHandlingProcessManager does not forward "mode" parameter to backing ProcessManager's "start" method

* Make "pub get" use ProcessStartMode.inheritStdio instead of forwarding bytes to stdout and stderr

* Fix tests

* Remove unused env var

* Add back 'Running "flutter pub get"...' status log

* Fix indent

* Add Pub.test() constructor which lets tests mock stdio