Remove unused and invalid method

a) there is no `$this->_getDomConfigModel()` method
b) method is unused

Author: adragus-inviqa

lib/internal/Magento/Framework/Config/View.php

@@ -133,16 +133,6 @@ public function getMediaAttributes($module, $mediaType, $mediaId)
             : [];
     }
 
-    /**
-     * Return copy of DOM
-     *
-     * @return \Magento\Framework\Config\Dom
-     */
-    public function getDomConfigCopy()
-    {
-        return clone $this->_getDomConfigModel();
-    }
-
     /**
      * Variables are identified by module and name
      *