warning fix

com.unity.perception/Editor/Visualizer/VisualizerInstaller.cs

             var project = Application.dataPath;
             if (!CheckIfVisualizerInstalled(project))
             {
-                if (EditorUtility.DisplayDialog("Visualizer not Installed",
+                if (EditorUtility.DisplayDialog("Visualizer Not Installed",
-                    SetupVisualizer();
+                    await SetupVisualizer();
                 }
 
                 return;