[flutter_releases] Flutter Dev 2.3.0-12.1.pre Framework Cherrypicks (flutter#82852)

* enable uwp embedding in dev
* add tests

Author: christopherfujino

packages/flutter_tools/lib/src/features.dart

@@ -301,6 +301,10 @@ const Feature windowsUwpEmbedding = Feature(
     available: true,
     enabledByDefault: false,
   ),
+  dev: FeatureChannelSetting(
+    available: true,
+    enabledByDefault: false,
+  ),
 );
 
 /// A [Feature] is a process for conditionally enabling tool features.

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

@@ -467,6 +467,19 @@ void main() {
       expect(featureFlags.isWindowsUwpEnabled, true);
     });
 
+    testWithoutContext('Flutter Windows UWP desktop off by default on dev', () {
+      final FeatureFlags featureFlags = createFlags('dev');
+
+      expect(featureFlags.isWindowsUwpEnabled, false);
+    });
+
+    testWithoutContext('Flutter Windows UWP desktop enabled with config on dev', () {
+      final FeatureFlags featureFlags = createFlags('dev');
+      testConfig.setValue('enable-windows-uwp-desktop', true);
+
+      expect(featureFlags.isWindowsUwpEnabled, true);
+    });
+
     testWithoutContext('Flutter Windows UWP desktop off by default on stable', () {
       final FeatureFlags featureFlags = createFlags('stable');