Log file listing should handle incomplete multi-part checkpoints

[OussamaSaoudi-db]

Describe the bug

When constructing a LogSegment, we scan the _delta_log directory for checkpoints and commits. The most recent checkpoint is collected from the log, but the kernel does not check that it has collected a full multi-part checkpoint. Thus, the checkpoint returned may be incomplete.

To Reproduce

This behaviour can be seen in the LogSegment test build_snapshot_with_missing_checkpoint_part_no_hint.

Expected behavior

build_snapshot_with_missing_checkpoint_part_no_hint should pass and return the most recent complete checkpoint at version 3.

Additional context

No response