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

Author: skumargupta83

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

@@ -5,6 +5,19 @@
   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 %}
@@ -30,4 +43,4 @@
         </div>
     {% endblock %}
 </form>
-{% endblock %}
+{% endblock %}