[Firebase AI] Increase the test timeout (#1289)

Author: a-maurice

firebaseai/testapp/Assets/Firebase/Sample/FirebaseAI/UIHandlerAutomated.cs

@@ -120,6 +120,9 @@ protected override void Start() {
         logFunc: DebugLog
       );
 
+      // Some of the AI tests tend to take a bit longer, so increase the timeout.
+      testRunner.TestTimeoutSeconds = 120f;
+
       base.Start();
     }