fix(ui): guard terminal writes while suspended

We forgot to guard `beep()` and `flush()`.

Ref: 36ec2b0ae1
Ref: dd76f9087f
Signed-off-by: Michael Vetter <jubalh@iodoru.org>
Fixes: https://github.com/profanity-im/profanity/issues/2162
(cherry picked from commit 5e4b5d313a9e055e039e2feb4efae58b6aaead78)

src/ui/chatwin.c

@@ -327,7 +327,7 @@ chatwin_incoming_msg(ProfChatWin* chatwin, ProfMessage* message, gboolean win_cr
             cons_show_incoming_message(display_name, num, chatwin->unread, window);
 
             if (prefs_get_boolean(PREF_FLASH)) {
-                flash();
+                ui_flash();
             }
 
             chatwin->unread++;
@@ -364,7 +364,7 @@ chatwin_incoming_msg(ProfChatWin* chatwin, ProfMessage* message, gboolean win_cr
         wins_add_quotes_ac(window, message->plain, FALSE);
 
         if (prefs_get_boolean(PREF_BEEP)) {
-            beep();
+            ui_beep();
         }
     }