MDL-75656 tag: decode entities in tags element values.

lib/form/tags.php

@@ -251,6 +251,13 @@ class MoodleQuickForm_tags extends MoodleQuickForm_autocomplete {
             return $this->_prepareValue([], $assoc);
         }
 
+        // Submitted tag data will be encoded, we want original text.
+        if (array_key_exists($this->getName(), $submitValues)) {
+            array_walk($submitValues[$this->getName()], static function(string &$tag): void {
+                $tag = html_entity_decode($tag);
+            });
+        }
+
         return parent::exportValue($submitValues, $assoc);
     }