Revert "fix: Multi Select course/courserun issue (#4702)"

This reverts commit 9a51f58.

Author: UsamaSadiq

course_discovery/apps/course_metadata/templates/admin/course_metadata/course_run.html

@@ -5,19 +5,6 @@
   change-program-excluded-course-runs-form
 {% endblock %}
 
-{% block extrastyle %}
-<link href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.13/css/select2.min.css" rel="stylesheet">
-{% endblock %}
-
-{% block extrahead %}
-<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.13/js/select2.min.js"></script>
-<script>
-    document.addEventListener('DOMContentLoaded', function() {
-        $('.select2').select2();
-    });
-</script>
-{% endblock %}
-
 {% block content %}
 <form class="form" method="post" action="">
     {% csrf_token %}
@@ -43,4 +30,4 @@
         </div>
     {% endblock %}
 </form>
-{% endblock %}
+{% endblock %}