[flutter_tools] Remove redundant/unused code in version.dart by @RoyARG02 in https://github.com/flutter/flutter/pull/105111

[flutter_tools] Fix leaky test by @christopherfujino in https://github.com/flutter/flutter/pull/105927

Remove unneeded date comment in gradle-wrapper.properties by @asashour in https://github.com/flutter/flutter/pull/104061

[flutter_tool] partial null safety migration of tool source code by @jonahwilliams in https://github.com/flutter/flutter/pull/105798

[flutter_tools] print override storage warning to STDERR instead of STDOUT by @christopherfujino in https://github.com/flutter/flutter/pull/106068