Fix Warning 'CS4014' in "UITests.App" project

The `SendLogMessage` method in the App class returns `Task` but
we didn't await where it is called, i.e. in the `LogMessage` method.
Thus, updating the method with async/await pattern fixes the warning.

Author: Nirmal4G

UITests/UITests.App/TestInterop.cs

@@ -28,7 +28,7 @@ public static void Error(string format, params object[] args)
             LogMessage("Error", "[Error] " + format, args);
         }
 
-        private static void LogMessage(string level, string format, object[] args)
+        private static async void LogMessage(string level, string format, object[] args)
         {
             // string.Format() complains if we pass it something with braces, even if we have no arguments.
             // To account for that, we'll escape braces if we have no arguments.
@@ -43,7 +43,7 @@ private static void LogMessage(string level, string format, object[] args)
 
             // Send back to Test Harness via AppService
             // TODO: Make this a cleaner connection/pattern
-            _ = ((App)Application.Current).SendLogMessage(level, message);
+            _ = await ((App)Application.Current).SendLogMessage(level, message);
         }
     }
 }