Fix IDE warning

Author: Evangelink

src/Adapter/MSTest.PlatformServices/Services/SettingsProvider.cs

@@ -1,7 +1,9 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+#if !WINDOWS_UWP
 using Microsoft.VisualStudio.TestPlatform.MSTestAdapter;
+#endif
 
 using MSTest.PlatformServices.Interface;