fix: dashboard

Author: NileTheKing

core-service/src/main/resources/templates/cohort-dashboard.html

@@ -7,6 +7,7 @@
     <script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/js/all.min.js"
         crossorigin="anonymous"></script>
+    <link rel="stylesheet" th:href="@{/css/dashboard.css}">
 </head>
 <section>
     <input type="hidden" id="activityId" th:value="${activityId}" />