During bucket-reopening, we perform bucket validation.

We don't:

• Propagate warnings of corrupted/malformed buckets from the bucket validation
• Incorporate logging of detecting a corrupted/malformed bucket
• Freeze the corrupted/malformed bucket

This ticket could be split out to also separate bucket validation into its own function

This should only apply to buckets for query-based reopening because once a user performs a direct bucket write, a bucket should only be eligible for query-based reopening.