Blazor CRUD uses NotFound() method instead of navigation

[ilonatommy]

This PR is updating Blazor CRUD scaffolder to use NavigationManager.NotFound() instead of NavigationManager.NavigateTo("notfound"). I am not sure how to apply all the necessary changes. I will list all the actions needed and would be grateful for help in completing it, cc @deepchoudhery, @tlmii.

Changes:

• ReplaceNavigateTo(\"notfound\") with NavigationManager.NotFound() Blazor CRUD.
• Add NotFound.razor page to the project that could be same as https://github.com/dotnet/aspnetcore/blob/main/src/ProjectTemplates/Web.ProjectTemplates/content/BlazorWeb-CSharp/BlazorWeb-CSharp/Components/Pages/NotFound.razor
• Add NotFoundPage parameter to Router, like here:
  https://github.com/dotnet/aspnetcore/blob/9a6b2eb7ee0eaffcdd3a361b06899b4fe735a4d6/src/ProjectTemplates/Web.ProjectTemplates/content/BlazorWeb-CSharp/BlazorWeb-CSharp/Components/Routes.razor#L7
• Add re-execution middleware with the route to NotFound.razor page in Program.cs, like here: https://github.com/dotnet/aspnetcore/blob/403d2161c6834f6e519ceac9e5eafa72a1e53b1b/src/ProjectTemplates/Web.ProjectTemplates/content/BlazorWeb-CSharp/BlazorWeb-CSharp/Program.cs#L99.
• Test the result.

[javiercn]

Should we have the scaffolder create the NotFound page if it doesn't exist? Similarly, add the required code (UseStatusCodePages and NotFoundPageType)

[danroth27]

Note that these changes are specific to .NET 10. For .NET 9 and earlier we'll need to continue to generate the existing code for handling not found responses.

premature