Fix MFA page showing up when not active on account switch (#5687)

webapp/actions/user_actions.jsx

@@ -645,7 +645,7 @@ export function checkMfa(loginId, success, error) {
         loginId,
         (data) => {
             if (success) {
-                success(data);
+                success(data && data.mfa_required === 'true');
             }
         },
         (err) => {

webapp/components/login/login_controller.jsx

@@ -131,8 +131,8 @@ export default class LoginController extends React.Component {
 
         checkMfa(
             loginId,
-            (data) => {
-                if (data && data.mfa_required === 'true') {
+            (requiresMfa) => {
+                if (requiresMfa) {
                     this.setState({showMfa: true});
                 } else {
                     this.submit(loginId, password, '');