Introduce a new property in CachingNoticeStream for always checking if there
are any new elements in the stream.
It would be extremely hard to blow InboxNoticeStream, so instead the database
hit will still occur, but it is be much faster than starting fresh.
This fixes a regression introduced in 36a55d8436
All verbs for not visible notices are filtered out, so this should not
break the timeline.
Additionally, filter by profile outside of the derived relation as that shows
better performance in PostgreSQL and MariaDB both.
It appears this was added to display "tombstones" of deleted notices.
However, it has other side-effects and the concept of keeping them visible has
not been adopted by the wider fediverse.
Alexei Sorokin
Miguel Dantas