Remove deprecated...

Remove deprecated TestWindow.platformBrightnessTestValue/TestWindow.clearPlatformBrightnessTestValue (#133178)

Part of: https://github.com/flutter/flutter/issues/133171

packages/flutter_test/lib/src/window.dart

@@ -1557,24 +1557,6 @@ class TestWindow implements SingletonFlutterWindow {
   set onPlatformBrightnessChanged(VoidCallback? callback) {
     platformDispatcher.onPlatformBrightnessChanged = callback;
   }
-  /// Hides the real text scale factor and reports the given
-  /// [platformBrightnessTestValue] instead.
-  @Deprecated(
-    'Use WidgetTester.platformDispatcher.platformBrightnessTestValue instead. '
-    'This feature was deprecated after v2.11.0-0.0.pre.'
-  )
-  set platformBrightnessTestValue(Brightness platformBrightnessTestValue) { // ignore: avoid_setters_without_getters
-    platformDispatcher.platformBrightnessTestValue = platformBrightnessTestValue;
-  }
-  /// Deletes any existing test platform brightness and returns to using the
-  /// real platform brightness.
-  @Deprecated(
-    'Use WidgetTester.platformDispatcher.clearPlatformBrightnessTestValue() instead. '
-    'This feature was deprecated after v2.11.0-0.0.pre.'
-  )
-  void clearPlatformBrightnessTestValue() {
-    platformDispatcher.clearPlatformBrightnessTestValue();
-  }
 
   @Deprecated(
     'Use WidgetTester.platformDispatcher.alwaysUse24HourFormat instead. '

packages/flutter_test/test/window_test.dart

@@ -106,7 +106,7 @@ void main() {
         return WidgetsBinding.instance.window.platformBrightness;
       },
       propertyFaker: (TestWidgetsFlutterBinding binding, Brightness fakeValue) {
-        binding.window.platformBrightnessTestValue = fakeValue;
+        binding.platformDispatcher.platformBrightnessTestValue = fakeValue;
       },
     );
   });