backstage release v2.91.2-rc.3

Changed

• (repositories) Reach Create repository only from the Repositories page in #2741 by @marians

Fixed

• (scaffolder) Refresh cluster tokens when a template is submitted in #2735 by @QuentinBisson
• (gs) Keep the sidebar without a main auth provider in #2742 by @teemow

Full Changelog: https://github.com/giantswarm/backstage/compare/v2.91.1...v2.91.2-rc.3