fix(ui): separate catalog icon masks from tiles

packages/ui/test/ui.test.ts

@@ -2983,6 +2983,7 @@ test("catalog mega menu renders only the active rail category", async () => {
   expect(dom.querySelectorAll(".wrn-mega__link-icon")).toHaveLength(0);
   expect(dom.querySelectorAll(".wrn-mega__link-description")).toHaveLength(0);
   expect(source).toContain("border-bottom: 1px solid var(--wrn-color-border)");
+  expect(source).toContain('.wrn-mega__rail-icon > span');
   expect(source).toContain("color: currentColor !important");
 });