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

[ericstj]

This issue will track removing all the temporary workarounds we add to #121853 in order to target .NET 11 with the .NET 10 SDK.

• 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 - this needs to be hardcoded since we don't have an 11.0 intellisense package yet.

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