Send an event when proxied DDS creates a connection. (#139530)

The event allows tools to listen and connect to the original DDS port.

packages/flutter_tools/lib/src/proxied_devices/devices.dart

@@ -775,6 +775,11 @@ class ProxiedDartDevelopmentService implements DartDevelopmentService {
 
     _localUri = remoteUri.replace(port: localPort);
     _logger.printTrace('Local port forwarded DDS on $_localUri.');
+    _logger.sendEvent('device.proxied_dds_forwarded', <String, String>{
+      'deviceId': deviceId,
+      'remoteUri': remoteUri.toString(),
+      'localUri': _localUri!.toString(),
+    });
   }
 
   @override

packages/flutter_tools/test/general.shard/proxied_devices/proxied_devices_test.dart

@@ -440,6 +440,11 @@ void main() {
 
       expect(dds.uri, Uri.parse('http://127.0.0.1:400/remote'));
 
+      expect(
+        bufferLogger.eventText.trim(),
+        '{"name":"device.proxied_dds_forwarded","args":{"deviceId":"test_id","remoteUri":"http://127.0.0.1:300/remote","localUri":"http://127.0.0.1:400/remote"}}',
+      );
+
       unawaited(dds.shutdown());
 
       final DaemonMessage shutdownMessage = await broadcastOutput.first;