Make oepn-ended responses and self-assessment answers use

the same CSS

common/lib/capa/capa/templates/openendedinput.html

@@ -1,5 +1,5 @@
 <section id="openended_${id}" class="openended">
-  <textarea rows="${rows}" cols="${cols}" name="input_${id}" id="input_${id}"
+  <textarea rows="${rows}" cols="${cols}" name="input_${id}" class="short-form-response" id="input_${id}"
        % if hidden:
       	    style="display:none;"
        % endif

lms/static/sass/course/courseware/_courseware.scss

@@ -241,15 +241,14 @@ div.course-wrapper {
   
 }
 
+textarea.short-form-response {
+    height: 200px;
+    padding: 5px;
+    margin-top: 5px;
+    margin-bottom: 5px;
+}
 
 section.self-assessment {
-    textarea.answer {
-        height: 200px;
-        padding: 5px;
-        margin-top: 5px;
-        margin-bottom: 5px;
-    }
-
     textarea.hint {
         height: 100px;
         padding: 5px;

lms/templates/self_assessment_prompt.html

@@ -6,7 +6,7 @@
     </div>
 
     <div>
-    <textarea name="answer" class="answer" cols="70" rows="20">${previous_answer|h}</textarea>
+    <textarea name="answer" class="answer short-form-response" cols="70" rows="20">${previous_answer|h}</textarea>
     </div>
 
     <div class="rubric-wrapper">${initial_rubric}</div>