[Blazor] Accept the `blazor.web.js` startup options format in `blazor.{server|webassembly}.js`

[MackinnonBuck]

Problem

When a Blazor app uses blazor.web.js, the options object passed to Blazor.start() has the following format:

Blazor.start({
  ssr: { /* ... */ },
  circuit: { /* ... */ },
  webAssembly: { /* ... */ },
});

However, when using blazor.server.js or blazor.webassembly.js, runtime-specific options are specified as top-level properties on the options object. So, for example, if you're using blazor.webassembly.js and you attempt to customize the loading of boot resources like this:

Blazor.start({
  webAssembly: {
    loadBootResource: function (/* ... */) {
      // ...
    },
  },
});

...then it will just silently "not work". This could create a pit of failure for customers who see examples in docs using the blazor.web.js options format but are writing a Blazor WebAssembly standalone app, for example.

Solution

We should update blazor.webassembly.js and blazor.server.js to accept the options format used by blazor.web.js.

Summary Comment: #51611 (comment)

Thanks for contacting us.

We're moving this issue to the .NET 9 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.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

Thanks for contacting us.

We're moving this issue to the .NET 9 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.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[mkArtakMSFT]

@MackinnonBuck can you please follow the https://aka.ms/aspnet/processes/help-wanted process to turn this into a help wanted issue? Thanks!