Feature band release PRs timing issue

When generating release PRs for feature bands, the pipeline logic relies on the public release metadata to indicate what the latest SDK release is. This creates a timing issue. The pipeline logic may run before the releases.json file gets updated. That may cause a PR to be created for a feature band that is EOL. See an example of this: https://github.com/dotnet/dotnet/pull/8237

Start by reviewing the pipeline logic that uses public release metadata and the releases.json file, then compare its behavior with the example PR #8237. Done means the pipeline no longer creates a release PR for an EOL feature band when releases.json has not yet been updated.

Written by the indexing model from the issue text.