Avoid looking up settings during timeline rendering (#8313)

* Avoid showHiddenEventsInTimeline lookups

* Avoid MSC3531 feature lookups

* Test that showHiddenEventsInTimeline doesn't get looked up while
rendering

* Fix code review nits

Co-authored-by: Travis Ralston <travisr@matrix.org>

src/components/structures/TimelinePanel.tsx

@@ -1511,7 +1511,7 @@ class TimelinePanel extends React.Component<IProps, IState> {
 
             const shouldIgnore = !!ev.status || // local echo
                 (ignoreOwn && ev.getSender() === myUserId); // own message
-            const isWithoutTile = !haveRendererForEvent(ev, this.context?.showHiddenEventsInTimeline) ||
+            const isWithoutTile = !haveRendererForEvent(ev, this.context?.showHiddenEvents) ||
                 shouldHideEvent(ev, this.context);
 
             if (isWithoutTile || !node) {