FIX: Don't require device capabilities when calculating login methods

app/assets/javascripts/discourse/controllers/preferences/second-factor.js.es6

@@ -34,13 +34,7 @@ export default Ember.Controller.extend({
 
   @computed
   displayOAuthWarning() {
-    return (
-      findAll(
-        this.siteSettings,
-        getOwner(this).lookup("capabilities:main"),
-        this.site.isMobileDevice
-      ).length > 0
-    );
+    return findAll().length > 0;
   },
 
   toggleSecondFactor(enable) {

app/assets/javascripts/discourse/models/login-method.js.es6

@@ -86,7 +86,10 @@ export function findAll(siteSettings, capabilities, isMobileDevice) {
   });
 
   // On Mobile, Android or iOS always go with full screen
-  if (isMobileDevice || capabilities.isIOS || capabilities.isAndroid) {
+  if (
+    isMobileDevice ||
+    (capabilities && (capabilities.isIOS || capabilities.isAndroid))
+  ) {
     methods.forEach(m => m.set("full_screen_login", true));
   }