remove deprecated `author` fields (#84997)

dev/devicelab/pubspec.yaml

 name: flutter_devicelab
-author: Flutter Authors <flutter-dev@googlegroups.com>
 description: Flutter continuous integration performance and correctness tests.
 homepage: https://github.com/flutter/flutter
 

dev/snippets/pubspec.yaml

 name: snippets
 version: 0.1.0
-author: Flutter Team <flutter-dev@googlegroups.com>
 description: A code snippet dartdoc extension for Flutter API docs.
 homepage: https://github.com/flutter/flutter
 

dev/tools/vitool/pubspec.yaml

@@ -2,7 +2,6 @@ name: vitool
 description: A tool for generating Dart vector animation code from SVG sequences.
 version: 0.0.1
 homepage: https://flutter.dev
-author: Flutter Authors <flutter-dev@googlegroups.com>
 
 environment:
   sdk: ">=2.12.0 <3.0.0"

packages/flutter/pubspec.yaml

 name: flutter
-author: Flutter Authors <flutter-dev@googlegroups.com>
 description: A framework for writing Flutter applications
 homepage: http://flutter.dev
 

packages/flutter/test_private/pubspec.yaml

 name: flutter_test_private
-author: Flutter Authors <flutter-dev@googlegroups.com>
 description: Tests private interfaces of the flutter
 
 environment:

packages/flutter/test_private/test/pubspec.yaml

 name: animated_icons_private_test
-author: Flutter Authors <flutter-dev@googlegroups.com>
 
 environment:
   sdk: ">=2.12.0-0 <3.0.0"

packages/flutter_driver/pubspec.yaml

 name: flutter_driver
 description: Integration and performance test API for Flutter applications
 homepage: http://flutter.dev
-author: Flutter Authors <flutter-dev@googlegroups.com>
 
 environment:
   sdk: ">=2.12.0-0 <3.0.0"

packages/flutter_tools/pubspec.yaml

 name: flutter_tools
 description: Tools for building Flutter applications
 homepage: https://flutter.dev
-author: Flutter Authors <flutter-dev@googlegroups.com>
 
 environment:
   sdk: ">=2.12.0-0 <3.0.0"

packages/flutter_web_plugins/pubspec.yaml

 name: flutter_web_plugins
 description: Library to register Flutter Web plugins
-author: Flutter Authors <flutter-dev@googlegroups.com>
 homepage: http://flutter.dev
 
 environment:

packages/integration_test/integration_test_macos/pubspec.yaml

 name: integration_test_macos
 description: Desktop implementation of integration_test plugin
 version: 0.0.1+1
-author: Flutter Team <flutter-dev@googlegroups.com>
 homepage: https://github.com/flutter/plugins/tree/master/packages/integration_test/integration_test_macos
 
 flutter: