Refresh signatures of test UDFs made with soon-expiring subkeys

These test UDFs were signed by a subkey that will expire in January 2025. If we don't update them, we'll see test suite failures all over the place.

Also, we need this for !1863 (merged): without this update, the test UDFs were signed with a subkey for which the minimal version of the key that's our website lacks a self-sig that was valid at the time the signature was made, so Sequoia won't consider the signature as valid in our automated test where we empty the local copy of the key and only use the version downloaded from our website (which is a bit more extreme than what would happen on real user system if a subkey expired; it's safer and easier to test this worst case).