get rid of (most of) have_events from _update_auth_events_and_context_for_auth (#6468)

have_events was a map from event_id to rejection reason (or None) for events
which are in our local database. It was used as filter on the list of
event_ids being passed into get_events_as_list. However, since
get_events_as_list will ignore any event_ids that are unknown or rejected, we
can equivalently just leave it to get_events_as_list to do the filtering.

That means that we don't have to keep `have_events` up-to-date, and can use
`have_seen_events` instead of `get_seen_events_with_rejection` in the one place
we do need it.

1 files changed, 1 insertions, 0 deletions

diff --git a/changelog.d/6468.misc b/changelog.d/6468.misc
new file mode 100644
index 0000000000..d9a44389b9
--- /dev/null
+++ b/changelog.d/6468.misc
@@ -0,0 +1 @@
+Refactor some code in the event authentication path for clarity.