rofi: fix brotab script calling itself when selecting tab

config/etc/rofi.rasi.nix

@@ -4,13 +4,13 @@ let
     with pkgs; # bash
     ''
       #!/usr/bin/env bash
-      if [ -z ''${1} ]; then
+      if [ -z "''${1}" ]; then
         ${brotab}/bin/bt list;
       else
         TARGET_TAB=$(sed "s/\t.*$//g" <<< ''${1});
         # activate window as focused to it is easy to switch to
         ${brotab}/bin/bt activate --focused ''${TARGET_TAB} > /dev/null 2>&1;
-        if [ -n ''${SWAYSOCK} ] && which swaymsg; then
+        if [ -n ''${SWAYSOCK} ] && which swaymsg >/dev/null 2>&1; then
           swaymsg "[urgent=latest] focus" > /dev/null 2>&1;
         fi
       fi