Fix invalid default values when editing user options

The submitted default value is validated in `UserOptionAddForm` depending on the submitted option type. But when editing a user option there will be no option type submitted, because it is not allowed to change the option type of an existing option.

https://www.woltlab.com/community/thread/310689

Author: BurntimeX

wcfsetup/install/files/lib/acp/form/UserOptionEditForm.class.php

@@ -60,6 +60,8 @@ public function readParameters()
      */
     public function readFormParameters()
     {
+        $this->optionType = $this->userOption->optionType;
+
         parent::readFormParameters();
 
         $this->optionType = $this->userOption->optionType;
@@ -68,9 +70,7 @@ public function readFormParameters()
     /**
      * @inheritDoc
      */
-    protected function setDefaultOutputClass()
-    {
-    }
+    protected function setDefaultOutputClass() {}
 
     /**
      * @inheritDoc