fix(Stack): reduce offset y on hover (#1771)

Author: artemmufazalov

src/components/Stack/Stack.scss

@@ -3,7 +3,7 @@
     --ydb-stack-offset-x: 4px;
     --ydb-stack-offset-y: 4px;
     --ydb-stack-offset-x-hover: 4px;
-    --ydb-stack-offset-y-hover: 8px;
+    --ydb-stack-offset-y-hover: 6px;
 
     position: relative;