For workload feature bands, treat -rtm preview versions the same as the stabilized, non-preview versions #36500
Description
When calculating SDK feature bands for workloads, we ignore the prerelease specifier if it's -dev or -ci. We should probably update this to also ignore -rtm versions.
This is compounded by the fact that we don't parse -rtm versions correctly. Since we normally expect a preview band of something like -preview.7 or -rc.1, when it comes to an SDK version such as 8.0.100-rtm.23526.1, we end up with a feature band of 8.0.100-rtm.23526, which is wrong.