feat(flutter): 重构播放页并增加语言切换

test/discover/home_all_dramas_grid_test.dart

@@ -32,7 +32,7 @@ void main() {
     expect(find.text('Continue Watching'), findsNothing);
     expect(find.byKey(const Key('discover-search')), findsOneWidget);
     expect(find.byKey(const Key('theater-category-chips')), findsOneWidget);
-    expect(find.byKey(const Key('theater-language-chips')), findsOneWidget);
+    expect(find.byKey(const Key('theater-language-chips')), findsNothing);
     expect(find.byKey(const Key('home-all-dramas-grid')), findsOneWidget);
     expect(tester.takeException(), isNull);
   });