Minor fixes for types in AsyncRequestClient

It seems there was a typo in the parameter.

PiperOrigin-RevId: 323307625
diff --git a/lib/src/common/request_client.dart b/lib/src/common/request_client.dart
index bd28618..dcd9e39 100644
--- a/lib/src/common/request_client.dart
+++ b/lib/src/common/request_client.dart
@@ -66,7 +66,8 @@
   WebDriverResponse sendRaw(WebDriverRequest request);
 }
 
-typedef AsyncWebDriverListener = Future Function(WebDriverCommandEvent event);
+typedef AsyncWebDriverListener = Future<dynamic> Function(
+    WebDriverCommandEvent event);
 
 /// Async client to send to and receive from WebDriver.
 abstract class AsyncRequestClient extends RequestClient {
@@ -74,7 +75,7 @@
 
   AsyncRequestClient(Uri prefix) : super(prefix);
 
-  void addEventListener(SyncWebDriverListener listener) {
+  void addEventListener(AsyncWebDriverListener listener) {
     _commandListeners.add(listener);
   }