This commit renames the 'queue_json_publish' function to
'queue_json_publish_rollback_unsafe' to reflect the fact that it doesn't
wait for the db transaction (within which it gets called, if any)
to commit and sends event irrespective of commit or rollback.
In most of the cases we don't want to send event in the case of
rollbacks, so the caller should be aware that calling the function
directly is rollback unsafe.
Fixes part of #30489.
This leads to significant speedups. In a test, with 100 random unique
event classes, the old code processed a batch of 100 rows (on average
66-ish unique in the batch) in 0.45 seconds. Doing this in a single
query processes the same batch in 0.0076 seconds.
