[Blazor] Blazor single project experience follow ups

We already checked-in initial support for the single project experience in the SDK. Based on exploratory testing with the template, we've discovered a set of issues we need to address to get into a functional template:

- [x] Fix service worker being incorrectly included. https://github.com/dotnet/aspnetcore/pull/49076
- [ ] Set StaticWebAssetBasePath unconditionally to `/` in multi-targeting builds on the .NET 8.0 project. https://github.com/dotnet/sdk/pull/33649
- [ ] Put the embedded configuration rule in the web SDK https://github.com/dotnet/sdk/pull/33649
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browser


```
- [ ] Adjust the conventions on the targets. Fix similar conventions for content https://github.com/dotnet/sdk/pull/33649
```

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- [ ] Resolve conflicts on the template
* App styles bundle. Covered as part of https://github.com/dotnet/aspnetcore/issues/47885
* Configuration files. We need to update the Wasm SDK to provide a `AssetMergeBehavior`
- [ ] Get rid of the loading UI https://github.com/dotnet/aspnetcore/issues/49056