[workloads] Prerelease sdkband workload versioning should key off the nuget package version by default

[lewing]

Using the package name for sdkband prerelease versioning breaks consistent dependency flow through darc and requires too much manual intervention. The default case should use the package version to determine the prerelease band. Additional opt in/out behaviors could be controlled via a fixed set of package name conventions.

[lewing]

More discussion in #15366 and dotnet/runtime#81235 (comment)

I meant to open this in dotnet/sdk but it seems I can't transfer it

[lewing]

#15380 dotnet/runtime#81398 dotnet/runtime#81399

[lewing]

This idea was rejected because the tasks all key off the package name so the proposed fix is flowing an stable named package through darc so we'll have to make a dummy pack dotnet/emsdk to handle the dummy flow which will require more work.

cc @steveisok

[baronfel]

@lewing let us know if there's anything else to do here and we can reopen.