Only run migration if impala isn't there

migrations/1751887718.sh

@@ -1,3 +1,5 @@
 echo "Install Impala as new wifi selection TUI"
-yay -S --noconfirm --needed impala
-gum confirm "Overwrite Waybar config to use Impala Wi-Fi selector in top bar?" && omarchy-refresh-waybar
+if ! command -v impala &>/dev/null; then
+  yay -S --noconfirm --needed impala
+  gum confirm "Overwrite Waybar config to use Impala Wi-Fi selector in top bar?" && omarchy-refresh-waybar
+fi