MDL-12079 fixed use of clean_param()

question/type/essay/questiontype.php

@@ -110,8 +110,7 @@ function print_question_formulation_and_controls(&$question, &$state, $cmoptions
 
     function grade_responses(&$question, &$state, $cmoptions) {
         // All grading takes place in Manual Grading
-
-        clean_param($state->responses[''], PARAM_CLEANHTML);
+        $state->responses[''] = clean_param($state->responses[''], PARAM_CLEAN);
 
         $state->raw_grade = 0;
         $state->penalty = 0;