Fix main timeline pending events bleeding in thread's timeline (#7373)

src/components/structures/TimelinePanel.tsx

@@ -1222,9 +1222,11 @@ class TimelinePanel extends React.Component<IProps, IState> {
         // should use this list, so that they don't advance into pending events.
         const liveEvents = [...events];
 
+        const thread = events[0]?.getThread();
+
         // if we're at the end of the live timeline, append the pending events
         if (!this.timelineWindow.canPaginate(EventTimeline.FORWARDS)) {
-            events.push(...this.props.timelineSet.getPendingEvents());
+            events.push(...this.props.timelineSet.getPendingEvents(thread));
         }
 
         return {

src/components/views/rooms/EventTile.tsx

@@ -513,7 +513,7 @@ export default class EventTile extends React.Component<IProps, IState> {
         const room = this.context.getRoom(this.props.mxEvent.getRoomId());
         const notifications = RoomNotificationStateStore.instance.getThreadsRoomState(room);
 
-        this.threadState = notifications.threadsState.get(thread);
+        this.threadState = notifications.getThreadRoomState(thread);
 
         this.threadState.on(NotificationStateEvents.Update, this.onThreadStateUpdate);
         this.onThreadStateUpdate();