Ensure OSS licenses list up-to-date

[LGro]

Add a check to CI/CD that the listed open source licenses for the project dependencies are up-to-date; block release if they aren't.

For example, use flutter_oss_licenses to re-generate oss_licenses.dart and check if it changed.

[LGro]

Some tools like the internationalization is executed automatically on flutter pub get, can we do the same for generating the oss licenses list?