Investigate Prebuilts from .NET 10.0 Transition

[ellahathaway]

After the work from dotnet/sdk#43015 is finished, we should go back and investigate the cause of the prebuilts that were introduced in that PR and other prebuilts that were added to the tarball as a result of the transition to .NET 10.0.

The simple cause for the prebuilts could that the MSFT and source-build sdk/artifacts do not align. The simple fix for this would be to rebootstrap source-build to update the n-1 artifacts and then remove the remove the prebuilts tarball.

After the investigation has been completed, we should remove the prebuilts tarball.

[MichaelSimons]

[Triage]This is blocked on the following:

1. Adding 9.0 GA targeting packs to SBRP
2. Rebootstrap to an 10.0 SDK that references 9.0 GA