feat: customize edge arrow #918 (#1338)

### What problem does this PR solve?

feat: customize edge arrow #918 

### Type of change


- [x] New Feature (non-breaking change which adds functionality)

web/src/pages/flow/canvas/node/index.less

@@ -16,7 +16,8 @@
   // justify-self: center;
   justify-content: center;
   .nodeName {
-    font-size: 8px;
+    font-size: 10px;
+    color: black;
   }
   label {
     display: block;
@@ -31,7 +32,7 @@
   }
   .bottomBox {
     position: absolute;
-    bottom: -26px;
+    bottom: -34px;
     background: white;
     padding: 2px 5px;
     border-radius: 5px;