[Backport release-25.11] vault: 1.20.4 -> 1.21.1, vault-bin: 1.20.4 -> 1.21.1

[nixpkgs-ci[bot]]

Bot-based backport to release-25.11, triggered by a label in #463294.

Before merging, ensure that this backport is acceptable for the release.

Even as a non-committer, if you find that it is not acceptable, leave a comment.

[!TIP] If you maintain all packages touched by this pull request, and they are all located under pkgs/by-name/*, you can comment @NixOS/nixpkgs-merge-bot merge to automatically merge this PR using the nixpkgs-merge-bot.