Update Blazor Server App template name to `BlazorApp` (#29764)

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

@@ -445,7 +445,7 @@
       "path": "BlazorServerWeb-CSharp.csproj"
     }
   ],
-  "defaultName": "WebApplication",
+  "defaultName": "BlazorApp",
   "postActions": [
     {
       "condition": "(!skipRestore)",