Feature bands: Consume previous SDK instead of current

[mthalman]

Feature band branches (2xx+) are currently configured to consume the SDK of the current dependent 1xx build rather than the 1xx release. In other words, 10.0.200 should be using 10.0 RC 2 SDK instead of 10.0 RTM SDK, assuming that RTM is the current in-development version.

This version of the SDK is brought into the build here: https://github.com/dotnet/dotnet/blob/8e9bcd2241dc2cd18d03cab19c230294a77c3ce8/eng/pipelines/templates/jobs/vmr-build.yml#L415-L419

It's basing the version it retrieves on this value: https://github.com/dotnet/dotnet/blob/8e9bcd2241dc2cd18d03cab19c230294a77c3ce8/eng/Version.Details.props#L11

Instead, it should be basing it on this value: https://github.com/dotnet/dotnet/blob/8e9bcd2241dc2cd18d03cab19c230294a77c3ce8/eng/Versions.props#L28

This is dependent on https://github.com/dotnet/release/issues/1575. Related to #5332.