[Fix-5830][Improvement][UI] Improve the selection style in dag edit dialog (#5829)

* improve the selection style

* update another file

* remove unnecessary css part.

dolphinscheduler-ui/src/js/conf/home/pages/dag/_source/dag.vue

@@ -893,4 +893,12 @@
   .operBtn {
     padding: 8px 6px;
   }
+
+  .el-drawer__body {
+    ::selection {
+      background: #409EFF;
+      color: white;
+    }
+  }
+
 </style>

dolphinscheduler-ui/src/js/conf/home/pages/dag/_source/udp/udp.vue

@@ -251,6 +251,11 @@
       max-height: 600px;
       overflow-y: scroll;
       padding:0 20px;
+
+      ::selection {
+        background: #409EFF ;
+        color: white;
+      }
     }
     .title {
       line-height: 36px;