style: decentralized less var (#8369)

* style: decentralized less var

* chore: remove emtpy var file

src/pagination/index.less

@@ -1,4 +1,4 @@
-@import '../style/var.less';
+@import './var.less';
 
 .van-pagination {
   display: flex;

src/pagination/var.less

@@ -0,0 +1,11 @@
+@import '../style/var.less';
+
+@pagination-height: 40px;
+@pagination-font-size: @font-size-md;
+@pagination-item-width: 36px;
+@pagination-item-default-color: @blue;
+@pagination-item-disabled-color: @gray-7;
+@pagination-item-disabled-background-color: @background-color;
+@pagination-background-color: @white;
+@pagination-desc-color: @gray-7;
+@pagination-disabled-opacity: @disabled-opacity;