Remove "beta-quality" for Windows (#98614)

packages/flutter_tools/lib/src/features.dart

@@ -135,7 +135,7 @@ const Feature flutterLinuxDesktopFeature = Feature(
 
 /// The [Feature] for Windows desktop.
 const Feature flutterWindowsDesktopFeature = Feature(
-  name: 'beta-quality support for desktop on Windows',
+  name: 'support for desktop on Windows',
   configSetting: 'enable-windows-desktop',
   environmentOverride: 'FLUTTER_WINDOWS',
   master: FeatureChannelSetting(

packages/flutter_tools/test/general.shard/features_test.dart

@@ -106,7 +106,7 @@ void main() {
 
     testWithoutContext('Flutter Windows desktop help string', () {
       expect(flutterWindowsDesktopFeature.generateHelpMessage(),
-      'Enable or disable beta-quality support for desktop on Windows. '
+      'Enable or disable support for desktop on Windows. '
       'This setting will take effect on the master, dev, beta, and stable channels.');
     });