fix(cli): execute as expected if `ksh_arrays` is set (#11629)

lib/cli.zsh

@@ -11,7 +11,7 @@ function omz {
 
   # Subcommand functions start with _ so that they don't
   # appear as completion entries when looking for `omz`
-  (( $+functions[_omz::$command] )) || {
+  (( ${+functions[_omz::$command]} )) || {
     _omz::help
     return 1
   }