Tidy up credentials arguments

Author: mansurpasha

src/guardian/index.js

@@ -20,12 +20,7 @@ const failTitleLog = chalk.redBright.underline.bold;
 
 class GuardianCI {
   constructor(program) {
-    AWS.config.credentials = getAWSCredentials(
-      program.profile,
-      program,
-      null,
-      true
-    );
+    AWS.config.credentials = getAWSCredentials(program.profile, program);
     if (program.region) {
       AWS.config.region = program.region;
     }

src/services/awsCredentials.js

@@ -2,12 +2,11 @@ import AWS from "aws-sdk";
 
 import { promptMfaModal } from "../modals";
 
-function getAWSCredentials(profile, program, screen, isGuardian = false) {
+function getAWSCredentials(profile, program, screen) {
   let codeFn;
   if (program.mfa) {
-    const token = program.mfa;
-    codeFn = (serial, callback) => callback(null, token);
-  } else if (!isGuardian) {
+    codeFn = (serial, callback) => callback(null, program.mfa);
+  } else if (screen) {
     codeFn = (serial, callback) => promptMfaModal(callback, screen);
   } else {
     codeFn = () =>