[server] remove unused module (#12694)

src/server/lib/commander_extensions.js

@@ -1,9 +0,0 @@
-export default function (program) {
-  function isCommand(val) {
-    return typeof val === 'object' && val._name;
-  }
-
-  program.isCommandSpecified = function () {
-    return program.args.some(isCommand);
-  };
-}