don't warn for non-matching device discoverers (#25440)

* don't warn for non-matching device discoverers

* remove an out of date test

packages/flutter_tools/lib/src/commands/daemon.dart

@@ -579,21 +579,6 @@ class DeviceDomain extends Domain {
     if (!discoverer.supportsPlatform)
       return;
 
-    if (!discoverer.canListAnything) {
-      // This event will affect the client UI. Coordinate changes here
-      // with the Flutter IntelliJ team.
-      sendEvent(
-        'daemon.showMessage',
-        <String, String>{
-          'level': 'warning',
-          'title': 'Unable to list devices',
-          'message':
-              'Unable to discover ${discoverer.name}. Please run '
-              '"flutter doctor" to diagnose potential issues',
-        },
-      );
-    }
-
     _discoverers.add(discoverer);
 
     discoverer.onAdded.listen(_onDeviceEvent('device.added'));

packages/flutter_tools/test/commands/daemon_test.dart

@@ -179,28 +179,6 @@ void main() {
       await commands.close();
     });
 
-    testUsingContext('daemon should send showMessage on startup if no Android devices are available', () async {
-      final StreamController<Map<String, dynamic>> commands = StreamController<Map<String, dynamic>>();
-      final StreamController<Map<String, dynamic>> responses = StreamController<Map<String, dynamic>>();
-      daemon = Daemon(
-          commands.stream,
-          responses.add,
-          notifyingLogger: notifyingLogger,
-      );
-
-      final Map<String, dynamic> response =
-        await responses.stream.skipWhile(_isConnectedEvent).first;
-      expect(response['event'], 'daemon.showMessage');
-      expect(response['params'], isMap);
-      expect(response['params'], containsPair('level', 'warning'));
-      expect(response['params'], containsPair('title', 'Unable to list devices'));
-      expect(response['params'], containsPair('message', contains('Unable to discover Android devices')));
-    }, overrides: <Type, Generator>{
-      AndroidWorkflow: () => MockAndroidWorkflow(canListDevices: false),
-      IOSWorkflow: () => MockIOSWorkflow(),
-      FuchsiaWorkflow: () => MockFuchsiaWorkflow(),
-    });
-
     testUsingContext('device.getDevices should respond with list', () async {
       final StreamController<Map<String, dynamic>> commands = StreamController<Map<String, dynamic>>();
       final StreamController<Map<String, dynamic>> responses = StreamController<Map<String, dynamic>>();