Remove temporary .NET 11 targeting workarounds after we get a .NET 11 SDK

This issue will track removing all the temporary workarounds we add to https://github.com/dotnet/runtime/pull/121853 in order to target .NET 11 with the .NET 10 SDK.

- [x] Use .NET 10 pruning data when targeting .NET 11.
- Note: a potentially better fix would be to pre-generate the live pruning data before restore and use this instead of the SDK's targeting pack data. We were missing this in .NET 10 too. I looked into doing this, but it may not be sufficient for net11 retargeting since we have other subsets that don't consume the live targeting pack.

- [ ] Revert hardcoding in [IntellisensePackageXmlFilePathFromNetVersionFolder](https://github.com/dotnet/runtime/blob/f81f82551403fa8e3b9dc79234caa7b915d653c0/eng/intellisense.targets#L9) - this needs to be hardcoded since we don't have an 11.0 intellisense package yet.
- [x] Update NetCurrent in https://github.com/dotnet/dotnet/blob/3e4f63732a2e61ad7ae1d567e820f70b2a55c2f1/src/arcade/src/Microsoft.DotNet.Arcade.Sdk/tools/TargetFrameworkDefaults.props#L14
- [x] Remove explicit net11.0 target in windowsdesktop
- [x] Remove net10.0 target from dotnet/runtime packages in sourcebuild