os/bluestore: accept undecodable multi-block bluefs transactions on log

os/bluestore: accept undecodable multi-block bluefs transactions on log
replay.

We should proceed with OSD startup when detecting undecodable bluefs
transaction spanning multiple disk blocks during log replay.
The rationale is that such a transaction might appear during unexpected
power down - just not every disk block is written to disk. Hence we can
consider this a normal log replay stop condition.

https://tracker.ceph.com/issues/52079

Signed-off-by: Igor Fedotov <ifedotov@suse.com>