Fix NeoChatRoom::directChatRemoteMember

- Don't access member that's not there
- Use NeoChatRoomMember instead of RoomMember

BUG: 492733


(cherry picked from commit 2a5359e73b)

Co-authored-by: Tobias Fella <fella@posteo.de>

src/neochatroom.cpp

@@ -1705,9 +1705,13 @@ int NeoChatRoom::maxRoomVersion() const
     return maxVersion;
 }
 
-Quotient::RoomMember NeoChatRoom::directChatRemoteMember() const
+NeochatRoomMember *NeoChatRoom::directChatRemoteMember()
 {
-    return directChatMembers()[0];
+    if (directChatMembers().size() == 0) {
+        qWarning() << "No other member available in this room";
+        return {};
+    }
+    return new NeochatRoomMember(this, directChatMembers()[0].id());
 }
 
 void NeoChatRoom::sendLocation(float lat, float lon, const QString &description)