[Blazor] Fix CustomElements package including JavaScript config files as Content (#63200)

* Fix the package layout by removing unwanted files from the `content` and `contentFiles` folder(s)

Author: Copilot

src/Components/CustomElements/src/Microsoft.AspNetCore.Components.CustomElements.csproj

@@ -55,4 +55,11 @@
     </ItemGroup>
   </Target>
 
+  <!-- Exclude JavaScript configuration files from being packaged as Content -->
+  <ItemGroup>
+    <Content Remove="js\babel.config.json" />
+    <Content Remove="js\package.json" />
+    <Content Remove="js\tsconfig.json" />
+  </ItemGroup>
+
 </Project>