fix: tree growing space #502

Author: tangjinzhou

components/tree/style/index.less

@@ -22,7 +22,7 @@
   }
 
   li {
-    padding: 8px 0 0;
+    padding: 4px 0;
     margin: 0;
     list-style: none;
     white-space: nowrap;
@@ -164,7 +164,11 @@
       }
     }
   }
-
+  ul > li {
+    &:first-child {
+      padding-top: 4px;
+    }
+  }
   > li {
     &:first-child {
       padding-top: 7px;
@@ -178,6 +182,18 @@
     &-open {
       display: block;
     }
+    // https://github.com/ant-design/ant-design/issues/14958
+    > li {
+      // Provide additional padding between top child node and parent node
+      &:first-child {
+        padding-top: 8px;
+      }
+
+       // Hide additional padding between last child node and next parent node
+      &:last-child {
+        padding-bottom: 0;
+      }
+    }
   }
   li&-treenode-disabled {
     > span:not(.@{tree-prefix-cls}-switcher),