License Utility (#8460)
Created a utility for updating licenses in configured source files that can be run via tests and/or standalone.
https://github.com/flutter/devtools/issues/8216
* Initial YAML config parsing logic and tests
* added additional YAML config parsing logic
* Added comments and some logic to parse stored value
* renamed functions to better match functionality, added logic to return replacement header, and added more tests
* added support for bulk update
* added test for full repo check for incorrect licenses
* ran dart formatter
* fixed missing training commas
* moved license utils to tool
* fixed dependencies
* added github action to run tool tests
* added write permission to tool_tests.sh
* fixed Dartdoc function comment, experimenting with repo wide check test on CI
* excluding flutter-sdk dependencies from repo wide check
* test that the repo wide check actually catches incorrect license header
* Turned off repo wide check test
* addressed PR feedback
* addressed more PR feedback
* reverted some accidentally changed files, addressed additional PR feedback
* fixed DartDoc and other PR feedback
* added dry run option for bulk update
* corrected logic for test
* fixed missing trailing comma
* addressing some missed PR feedback
* removed late and added back final to member variables
* added clearer docs and removed unnecessary todo
* addressed missed PR feedback
* addressed another round of PR feedback
* fixed git issues
* additional PR feedback
* another round of PR feedback