This is so that the context of failing callbacks are not lost.
We also await during pagination and not after so that if a call to the callback fails, we will not call it again.
Related to https://github.com/matrix-org/mjolnir/pull/132.
The old code would call `/sync` with this filter. If a token was
provided in the response of `/sync` for earlier messages, it would
then use this same filter to call `/rooms/messages`. However, this
filter does not do anything on that endpoint when we know the id of
the sender, as it requires a RoomEventFilter and there is no warning
or error from synapse about the structure of the filter being wrong.
This was not noticed until after the related PR because `/sync` with
the filter would usually be able to provide a user's
entire history in one room. This is because in most cases a user is banned/redacted
shortly after joining a room.
In the case that `/rooms/messages` was called for more events, the method would
always paginate the timeline up until the limit or the end of the room
history, which is only the expected behavior when matching the sender
with a "glob".
