fix: Dont OMEMO trust check so often

a26cdf386b / #2104 added OMEMO trust status to the
title bar, but it was being re-calculated on UI refresh.

Update only on certain operations (like `/omemo trust`, new device
discoveries and even incoming OMEMO messages for example).

src/event/server_events.c

@@ -598,6 +598,8 @@ _sv_ev_incoming_omemo(ProfChatWin* chatwin, gboolean new_win, ProfMessage* messa
         chat_log_omemo_msg_in(message);
     }
     chatwin->pgp_recv = FALSE;
+
+    wins_omemo_trust_changed(chatwin->barejid);
 #endif
 }