fix: endpoint 被遮盖

Author: sdjalft

src/index.less

@@ -2,6 +2,9 @@
 
 .butterfly-monitor-dag {
   background: #2E2E2E;
+  .butterflie-circle-endpoint {
+    z-index: 500;
+  }
   .schedule-node {
     position: absolute;
     border: 1px solid #595959;