fix(sdk): Fix remote echo event_id check

The send-event response sets the event_id field, not the timeline key.
The previous error branch wasn't actually reachable.

Author: jplatte

crates/matrix-sdk/src/room/timeline/inner.rs

@@ -108,19 +108,11 @@ impl TimelineInner {
     pub(super) fn add_event_id(&self, txn_id: &TransactionId, event_id: OwnedEventId) {
         let mut lock = self.items.lock_mut();
         if let Some((idx, item)) = find_event_by_txn_id(&lock, txn_id) {
-            match &item.key {
-                TimelineKey::TransactionId(_) => {
-                    lock.set_cloned(
-                        idx,
-                        Arc::new(TimelineItem::Event(item.with_event_id(Some(event_id)))),
-                    );
-                }
-                TimelineKey::EventId(ev_id) => {
-                    if *ev_id != event_id {
-                        error!("remote echo and send-event response disagree on the event ID");
-                    }
-                }
+            if item.event_id.as_ref().map_or(false, |ev_id| *ev_id != event_id) {
+                error!("remote echo and send-event response disagree on the event ID");
             }
+
+            lock.set_cloned(idx, Arc::new(TimelineItem::Event(item.with_event_id(Some(event_id)))));
         } else {
             warn!(%txn_id, "Timeline item not found, can't add event ID");
         }