style: optimize layout rtl (#23921)

components/layout/style/index.less

@@ -123,3 +123,4 @@
 }
 
 @import './light';
+@import './rtl';

components/layout/style/rtl.less

@@ -0,0 +1,10 @@
+@import '../../style/themes/index';
+@import '../../style/mixins/index';
+
+@layout-prefix-cls: ~'@{ant-prefix}-layout';
+
+.@{layout-prefix-cls} {
+  &-rtl {
+    direction: rtl;
+  }
+}