style: move color var of table to default less (#3612)

Author: zkwolf

components/style/themes/default.less

@@ -540,6 +540,11 @@
 @table-footer-bg: @background-color-light;
 @table-footer-color: @heading-color;
 @table-header-bg-sm: transparent;
+// Sorter
+// Legacy: `table-header-sort-active-bg` is used for hover not real active
+@table-header-sort-active-bg: darken(@table-header-bg, 3%);
+// Filter
+@table-header-filter-active-bg: darken(@table-header-sort-active-bg, 5%);
 
 // Tag
 // --

components/table/style/index.less

@@ -3,8 +3,6 @@
 
 @table-prefix-cls: ~'@{ant-prefix}-table';
 @table-header-icon-color: #bfbfbf;
-@table-header-sort-active-bg: darken(@table-header-bg, 3%);
-@table-header-filter-active-bg: darken(@table-header-sort-active-bg, 5%);
 @table-selection-column-width: 60px;
 
 .@{table-prefix-cls}-wrapper {