[flutter_tools] clean plugin dependencies file (#62061)

Clean even more, in case the plugin dependency update logic is wrong-o.

packages/flutter_tools/lib/src/commands/clean.dart

@@ -57,6 +57,8 @@ class CleanCommand extends FlutterCommand {
     deleteFile(flutterProject.linux.ephemeralDirectory);
     deleteFile(flutterProject.macos.ephemeralDirectory);
     deleteFile(flutterProject.windows.ephemeralDirectory);
+    deleteFile(flutterProject.flutterPluginsDependenciesFile);
+    deleteFile(flutterProject.flutterPluginsFile);
 
     return const FlutterCommandResult(ExitStatus.success);
   }

packages/flutter_tools/test/commands.shard/hermetic/clean_test.dart

@@ -53,6 +53,8 @@ void main() {
         projectUnderTest.linux.ephemeralDirectory.createSync(recursive: true);
         projectUnderTest.macos.ephemeralDirectory.createSync(recursive: true);
         projectUnderTest.windows.ephemeralDirectory.createSync(recursive: true);
+        projectUnderTest.flutterPluginsFile.createSync(recursive: true);
+        projectUnderTest.flutterPluginsDependenciesFile.createSync(recursive: true);
       });
 
       testUsingContext('$CleanCommand removes build and .dart_tool and ephemeral directories, cleans Xcode', () async {
@@ -72,6 +74,9 @@ void main() {
         expect(projectUnderTest.macos.ephemeralDirectory.existsSync(), isFalse);
         expect(projectUnderTest.windows.ephemeralDirectory.existsSync(), isFalse);
 
+        expect(projectUnderTest.flutterPluginsFile.existsSync(), isFalse);
+        expect(projectUnderTest.flutterPluginsDependenciesFile.existsSync(), isFalse);
+
         verify(mockXcodeProjectInterpreter.cleanWorkspace(any, 'Runner', verbose: false)).called(2);
       }, overrides: <Type, Generator>{
         FileSystem: () => fs,