[flutter_tools] update some web configuration defaults (#71433)

packages/flutter_tools/lib/src/features.dart

@@ -134,15 +134,19 @@ const Feature flutterWebFeature = Feature(
   environmentOverride: 'FLUTTER_WEB',
   master: FeatureChannelSetting(
     available: true,
-    enabledByDefault: false,
+    enabledByDefault: true,
   ),
   dev: FeatureChannelSetting(
     available: true,
-    enabledByDefault: false,
+    enabledByDefault: flutterNext,
   ),
   beta: FeatureChannelSetting(
     available: true,
-    enabledByDefault: false,
+    enabledByDefault: flutterNext,
+  ),
+  stable: FeatureChannelSetting(
+    available: flutterNext,
+    enabledByDefault: flutterNext,
   ),
 );
 
@@ -378,3 +382,5 @@ class FeatureChannelSetting {
   /// If not provided, defaults to `false`.
   final bool enabledByDefault;
 }
+
+const bool flutterNext = false;

packages/flutter_tools/lib/src/isolated/resident_web_runner.dart

@@ -184,12 +184,14 @@ abstract class ResidentWebRunner extends ResidentRunner {
       fire + globals.terminal.bolden(rawMessage),
       TerminalColor.red,
     );
-    globals.printStatus(
-        "Warning: Flutter's support for web development is not stable yet and hasn't");
-    globals.printStatus('been thoroughly tested in production environments.');
-    globals.printStatus('For more information see https://flutter.dev/web');
-    globals.printStatus('');
-    globals.printStatus(message);
+    if (!flutterNext) {
+      globals.printStatus(
+          "Warning: Flutter's support for web development is not stable yet and hasn't");
+      globals.printStatus('been thoroughly tested in production environments.');
+      globals.printStatus('For more information see https://flutter.dev/web');
+      globals.printStatus('');
+      globals.printStatus(message);
+    }
     const String quitMessage = 'To quit, press "q".';
     if (device.device is! WebServerDevice) {
       globals.printStatus('For a more detailed help message, press "h". $quitMessage');