Using MapGroup with Blazor endpoints produces template error

[ptsoccer]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Similar to #57843, but when I use MapGroup to map blazor endpoints to a different base path, I get the error:

InvalidOperationException: Unable to find the provided template '/blazor/'

In the blazor template, I replace

app.MapStaticAssets();
app.MapRazorComponents<App>()
    .AddInteractiveWebAssemblyRenderMode()
    .AddAdditionalAssemblies(typeof(BlazorBasePath.Client._Imports).Assembly);

with

var groupBuilder = app.MapGroup("/blazor");

groupBuilder
    .MapStaticAssets();

groupBuilder
    .MapRazorComponents<App>()
    .AddInteractiveWebAssemblyRenderMode()
    .AddAdditionalAssemblies(typeof(BlazorBasePath.Client._Imports).Assembly);

I suppose the first question is, is that a valid thing to do? The issue I mentioned above does it using UsePathBase, but it seemed better to do what I want with the newer MapGroup feature.

Expected Behavior

Blazor site loads in new base path

Steps To Reproduce

Repo: https://github.com/ptsoccer/BlazorBasePath

1. Create new Blazor Web App with WebAssembly as the interactive render mode. Other render modes might also error out, but I need WebAssembly.
2. Replace

app.MapStaticAssets();
app.MapRazorComponents<App>()
    .AddInteractiveWebAssemblyRenderMode()
    .AddAdditionalAssemblies(typeof(BlazorBasePath.Client._Imports).Assembly);

with

var groupBuilder = app.MapGroup("/blazor");

groupBuilder
    .MapStaticAssets();

groupBuilder
    .MapRazorComponents<App>()
    .AddInteractiveWebAssemblyRenderMode()
    .AddAdditionalAssemblies(typeof(BlazorBasePath.Client._Imports).Assembly);

in the generated template

3. Run the website and browse to /blazor, you should get the error mentioned above.

Exceptions (if any)

No response

.NET Version

10.0.101

Anything else?

Microsoft.NETCore.App 10.0.1
Microsoft.AspNetCore.App 10.0.1