Tie nav spacing test to Tailwind padding

Author: klopez4212

desktop/tests/e2e/messaging.spec.ts

@@ -802,9 +802,13 @@ test("narrow thread view collapses channel header actions into a menu", async ({
   if (!menuBox || !threadPanelBox) {
     throw new Error("Expected header action menu and thread panel bounds");
   }
-  const menuGapPx = threadPanelBox.x - (menuBox.x + menuBox.width);
-  expect(menuGapPx).toBeGreaterThanOrEqual(10);
-  expect(menuGapPx).toBeLessThanOrEqual(14);
+  const menuGap = threadPanelBox.x - (menuBox.x + menuBox.width);
+  const headerPaddingInlineEnd = await page
+    .getByTestId("chat-header")
+    .evaluate((header) =>
+      Number.parseFloat(window.getComputedStyle(header).paddingRight),
+    );
+  expect(Math.round(menuGap)).toBe(Math.round(headerPaddingInlineEnd));
 
   await menuTrigger.click();