RenameDependencyPrefix updates issue IDs in the dependencies table but
was not rebuilding the blocked_issues_cache, leaving stale IDs in the
cache that no longer exist in the issues table.
Add invalidateBlockedCache() call at the end of RenameDependencyPrefix
to rebuild the cache with the new issue IDs.
Fixes: GH#1016
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>