refactor(e2e): organize fixtures by feature

e2e/specs/mock/auth/logout-from-sidebar.spec.ts

@@ -3,6 +3,7 @@ import { expect, test } from "@playwright/test";
 import { mockCoreApis } from "@e2e/fixtures/api-mocks";
 import {
   clearBrowserState,
+  getSplashStartChatButton,
   signInWithEmailAndOpenChat,
 } from "@e2e/fixtures/test-helpers";
 
@@ -26,8 +27,6 @@ test("user can log out from the sidebar after email login", async ({
   const logoutRequest = await logoutRequestPromise;
   expect(logoutRequest.method()).toBe("POST");
 
-  await expect(page).toHaveURL(/\/chat$/);
-  await expect(
-    page.getByRole("button", { name: "Sign up to unlock more features" }),
-  ).toBeVisible();
+  await expect(page).toHaveURL(/\/splash$/);
+  await expect(getSplashStartChatButton(page)).toBeVisible();
 });