Standardize slight variations in license format (#339)
- Uses the exact LICENSE file line breaking used in the other Flutter repositories
- Standardizes some slight textual variants in the license block (e.g., use of "(c)",
explicitly referencing the AUTHORS file) on the format used in the other repos.
[ci] Enable no_runtimeType_toString (#3129)
Enables the no_runtimeType_toString analysis option. This isn't part
of the base flutter/flutter analysis options, but is set in
flutter/packages which this repo better corresponds to.
This is already enabled in flutter/plugins, and is being enabled here as
part of aligning their options.
Part of https://github.com/flutter/flutter/issues/113764