Implement Blazor endpoint data source updates

[javiercn]

• Similar to how MVC/Razor pages does.

• We need to implement updates that can be triggered by things like hotreload, so that we can pick up changes on the metadata in the types that has changed or new elements that might have been added, like new pages.

• See https://github.com/dotnet/aspnetcore/blob/bec278eabea54f63da15e10e654bdfa4168a2479/src/Mvc/Mvc/src/HotReloadService.cs for details

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 8 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
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