MDL-87008 user: Set sticky footer for submit/cancel buttons.

public/user/edit_form.php

@@ -105,6 +105,7 @@ class user_edit_form extends moodleform {
         profile_definition($mform, $userid);
 
         $this->add_action_buttons(true, get_string('updatemyprofile'));
+        $mform->set_sticky_footer('buttonar');
 
         $this->set_data($user);
     }

public/user/editadvanced_form.php

@@ -162,6 +162,7 @@ class user_editadvanced_form extends moodleform {
         }
 
         $this->add_action_buttons(true, $btnstring);
+        $mform->set_sticky_footer('buttonar');
 
         $this->set_data($user);
     }