remove duplicated entry (#51880)

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

diff --git a/packages/flutter_tools/test/commands.shard/hermetic/run_test.dart b/packages/flutter_tools/test/commands.shard/hermetic/run_test.dart
index 9a9535e..51f018b 100644
--- a/packages/flutter_tools/test/commands.shard/hermetic/run_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/run_test.dart
@@ -537,7 +537,6 @@
         await createTestCommandRunner(command).run(args);
         expect(mockWebRunnerFactory._dartDefines, <String>['FOO=bar']);
       }, overrides: <Type, Generator>{
-        DeviceManager: () => mockDeviceManager,
         FeatureFlags: () => TestFeatureFlags(
           isWebEnabled: true,
         ),