[fzf-tmux] Fix race condition when using -l/-u on zoomed panes

Using a dummy command that works as the barrier.

bin/fzf-tmux

@@ -138,6 +138,7 @@ cleanup() {
 
   # Remove temp window if we were zoomed
   if [[ -n "$zoomed" ]]; then
+    tmux display-message -p "#{window_id}" > /dev/null
     tmux swap-pane -t $original_window \; \
       select-window -t $original_window \; \
       kill-window -t $tmp_window \; \