feat(2fa) Enable recovery code and fix form submit

issue #6059

ihtml/themes/breezy/secondfactor.tpl

@@ -8,6 +8,7 @@
 
 <div id="window-div">
 <form action="" method="post" id="loginform" name="loginform">
+  <div style="width: 0; height: 0; overflow: hidden;"><input type="submit" name="default_submit_hidden_button"/></div>
 
 {$msg_dialogs}
   <div id="window-titlebar">

include/login/class_LoginPost.inc

@@ -24,7 +24,7 @@
 class LoginPost extends LoginMethod
 {
   /*! \brief List of second factor methods, may be dynamic later */
-  static $secondFactorMethods = ['SecondFactorWebAuthn','SecondFactorTotp'];
+  static $secondFactorMethods = ['SecondFactorWebAuthn','SecondFactorTotp','SecondFactorRecoveryCode'];
 
   /*! \brief Displayed name */
   static function getLabel ()