Fix migration 42 when installing with pulpcore>=3.108

[gerrod3]

Can't rely on the gnupg dependency being there anymore.

📜 Checklist

• Commits are cleanly separated with meaningful messages (simple features and bug fixes should be squashed to one commit)
• A changelog entry or entries has been added for any significant changes
• Follows the Pulp policy on AI Usage
• (For new features) - User documentation and test coverage has been added

See: Pull Request Walkthrough

[mdellweg]

Should we need to provide a little bit more information somewhere.
If I read the rest of the file correctly, it is built to be resiliant but also talks about the repositories failed to migrate.
Otoh it's a rather old migration that just ever so slightly missed the (first) last squashing.
Can we purge migrations at this point and squash again?

[mdellweg]

I think we can get away with it, because every installation of a supported branch must have run this migration already.
Also:
#2517

[mdellweg]

I think we can get away with it, because every installation of a supported branch must have run this migration already.
Also:
#2517

[patchback]

Backport to 0.29: 💚 backport PR created

✅ Backport PR branch: patchback/backports/0.29/6a57fd0c5c688c2690274cc44926e47b72d92f9e/pr-2516

Backported as #2518

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