Fix RCL template to have correct filename for scoped CSS (#25870)

Author: SteveSandersonMS

src/ProjectTemplates/Web.ProjectTemplates/content/RazorClassLibrary-CSharp/.template.config/template.json

@@ -33,6 +33,7 @@
           "exclude": [
             "_Imports.razor",
             "Component1.razor",
+            "Component1.razor.css",
             "ExampleJsInterop.cs",
             "wwwroot/**"
           ]

src/ProjectTemplates/Web.ProjectTemplates/content/RazorClassLibrary-CSharp/Component1.razor.css

@@ -0,0 +1,6 @@
+.my-component {
+    border: 2px dashed red;
+    padding: 1em;
+    margin: 1em 0;
+    background-image: url('background.png');
+}