[extension_discovery] Drop unneeded dependency on pkg:lints (#207)

Author: kevmoo

pkgs/extension_discovery/pubspec.yaml

@@ -13,6 +13,5 @@ dependencies:
 dev_dependencies:
   collection: ^1.18.0
   dart_flutter_team_lints: ^2.0.0
-  lints: ^2.0.0
   test: ^1.21.0
   test_descriptor: ^2.0.1