Fixup Razor Class Library template namespace and component content (#13419)

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

 <div class="my-component">
-    This Blazor component is defined in the <strong>RazorClassLibrary-CSharp</strong> package.
+    This Blazor component is defined in the <strong>Company.RazorClassLibrary1</strong> package.
 </div>

src/ProjectTemplates/Web.ProjectTemplates/content/RazorClassLibrary-CSharp/ExampleJsInterop.cs

 using Microsoft.JSInterop;
 using System.Threading.Tasks;
 
-namespace RazorClassLibrary_CSharp
+namespace Company.RazorClassLibrary1
 {
     public class ExampleJsInterop
     {