MDL-44056 questions: restore essay attempts from 2.0 notice.

question/type/essay/db/upgradelib.php

@@ -62,6 +62,7 @@ public function supply_missing_first_step_data(&$data) {
     public function set_data_elements_for_step($state, &$data) {
         if (!empty($state->answer)) {
             $data['answer'] = $state->answer;
+            $data['answerformat'] = FORMAT_HTML;
         }
     }
 }