More invalid repo snapshots

[croissanne]

osbuild/images#1431

Failed to update some repositories/archs (9.6n) even though snapshots were available

[croissanne]

What seems to have happened is that it failed to properly build the enumerate cache, where a single key (el9-x86_64-google-cloud-sdk-20250417) was missing. Maybe weird s3 api caching issue?

Could investigate if there's a way to make sure we have all the keys; like maybe we gather the keys a few times and put them in a set?