Media Controls does not have a "DesignTools" project

Remove targets that requires "DesignTools" check to let build succeed.
Revert this patch when adding the actual "DesignTools" project for Media Controls.

Author: Nirmal4G

Microsoft.Toolkit.Uwp.UI.Controls.Media/Microsoft.Toolkit.Uwp.UI.Controls.Media.csproj

@@ -25,6 +25,7 @@
 
   <ItemGroup>
     <Compile Include="..\Microsoft.Toolkit.Uwp.UI.Controls.Core\ControlHelpers.XamlHost.cs" Link="ControlHelpers.XamlHost.cs" />
+    <None Include="VisualStudioToolsManifest.xml" Pack="true" PackagePath="tools" />
   </ItemGroup>
 
   <ItemGroup>
@@ -37,6 +38,4 @@
     <PackageReference Include="Win2D.uwp" Version="1.25.0" />
   </ItemGroup>
 
-  <Import Project="$(BuildToolsDirectory)Windows.Toolkit.Uwp.Controls.targets" />
-
 </Project>