DESIGN-4402 fix: 复选树视觉问题

src/less/base/tree/ztree.less

@@ -79,7 +79,6 @@
   vertical-align: top;
   display: inline-block;
 
-  .tree-node-text {
   &:not(.disabled) {
     &:hover {
       .background-color(@color-bi-background-highlight, 10%);
@@ -91,7 +90,6 @@
     }
   }
 }
-}
 
 .ztree.solid li a {
   height: 32px;
@@ -150,17 +148,12 @@
 
 .ztree li span.icon {
   display: inline-block;
-  vertical-align: top;
   text-align: center;
-  width: 24px;
-  height: 24px;
-  line-height: 24px;
-}
-
-.ztree li span.icon {
-  width: 32px;
-  height: 32px;
-  line-height: 32px;
+  width: 16px;
+  height: 16px;
+  line-height: 16px;
+  padding: 0 2px;
+  vertical-align: middle;
 }
 
 .ztree li span.button {