Added WebAssembly capability to Blazor WebAssembly projects

Addresses #28713

Author: mkArtakMSFT

src/Components/WebAssembly/Sdk/src/Sdk/Sdk.targets

@@ -15,6 +15,10 @@ Copyright (c) .NET Foundation. All rights reserved.
     <_BlazorWebAssemblyTargetsFile Condition="'$(_BlazorWebAssemblyTargetsFile)' == ''">$(MSBuildThisFileDirectory)..\targets\Microsoft.NET.Sdk.BlazorWebAssembly.Current.targets</_BlazorWebAssemblyTargetsFile>
   </PropertyGroup>
 
+  <ItemGroup>
+    <ProjectCapability Include="WebAssembly" />
+  </ItemGroup>
+  
   <Import Project="$(_BlazorWebAssemblyTargetsFile)" />
 
 </Project>