Remove collapse icon-- functionality not working.

Even when the icon is updated to fa, nothing happens when
the icon is clicked.

TNL-3799

openassessment/templates/openassessmentblock/edit/oa_edit_criterion.html

@@ -2,7 +2,7 @@
 {% spaceless %}
 <li class="openassessment_criterion is-collapsible" data-criterion="{{ criterion_name }}">
     <div class="openassessment_container_header openassessment_criterion_header view-outline">
-        <a class="action expand-collapse collapse"><i class="icon-caret-down ui-toggle-expansion"></i></a>
+        <a class="action expand-collapse collapse"></a>
         <div class="openassessment_container_header_title_box openassessment_criterion_header_title_box">
             <h6 class="openassessment_container_header_title openassessment_criterion_header_title">{% trans "Criterion" %}</h6>
             <p class="openassessment_container_guide openassessment_criterion_guide">{% trans "You cannot delete a criterion after the assignment has been released." %}</p>

openassessment/templates/openassessmentblock/edit/oa_edit_prompt.html

@@ -3,7 +3,7 @@
 <li class="openassessment_prompt is-collapsible" data-prompt="{{ prompt_uuid }}">
 
     <div class="openassessment_container_header openassessment_prompt_header view-outline">
-        <a class="action expand-collapse collapse"><i class="icon-caret-down ui-toggle-expansion"></i></a>
+        <a class="action expand-collapse collapse"></a>
         <div class="openassessment_container_header_title_box openassessment_prompt_header_title_box">
             <h6 class="openassessment_container_header_title openassessment_prompt_header_title">{% trans "Prompt" %}</h6>
             <p class="openassessment_container_guide openassessment_prompt_guide">{% trans "You cannot delete a prompt after the assignment has been released." %}</p>

openassessment/templates/openassessmentblock/edit/oa_training_example.html

@@ -3,9 +3,7 @@
 <li class="openassessment_training_example is-collapsible">
 
     <div class="openassessment_training_example_header view-outline">
-        <a class="action expand-collapse collapse">
-            <i class="icon-caret-down ui-toggle-expansion"></i>
-        </a>
+        <a class="action expand-collapse collapse"></a>
         <h6 class="openassessment_training_example_header_title">
             {% trans "Scored Response" %}
         </h6>