Revert "separate hydration tests for pages router" (#70218)

test/development/acceptance/hydration-error.test.ts

@@ -4,14 +4,9 @@ import { FileRef, nextTestSetup } from 'e2e-utils'
 import { outdent } from 'outdent'
 import path from 'path'
 
-// TODO: Enable this test once react 18 is supported for pages router
-describe.skip('Error overlay for hydration errors (React 18)', () => {
+describe('Error overlay for hydration errors', () => {
   const { next } = nextTestSetup({
     files: new FileRef(path.join(__dirname, 'fixtures', 'default-template')),
-    dependencies: {
-      react: '18.3.1',
-      'react-dom': '18.3.1',
-    },
     skipStart: true,
   })
 
@@ -38,13 +33,18 @@ describe.skip('Error overlay for hydration errors (React 18)', () => {
     await session.assertHasRedbox()
 
     expect(await session.getRedboxDescription()).toMatchInlineSnapshot(`
-      "Error: Text content does not match server-rendered HTML.
-      See more info here: https://nextjs.org/docs/messages/react-hydration-error"
-    `)
+        "Hydration failed because the server rendered HTML didn't match the client. As a result this tree will be regenerated on the client. This can happen if a SSR-ed Client Component used
+        See more info here: https://nextjs.org/docs/messages/react-hydration-error"
+      `)
+    expect(await session.getRedboxDescriptionWarning()).toMatchInlineSnapshot(`
+        "- A server/client branch \`if (typeof window !== 'undefined')\`.
+        - Variable input such as \`Date.now()\` or \`Math.random()\` which changes each time it's called.
+        - Date formatting in a user's locale which doesn't match the server.
+        - External changing data without sending a snapshot of it along with the HTML.
+        - Invalid HTML tag nesting.
 
-    expect(await session.getRedboxDescriptionWarning()).toMatchInlineSnapshot(
-      `"Text content did not match. Server: "server" Client: "client""`
-    )
+        It can also happen if the client has a browser extension installed which messes with the HTML before React loaded."
+      `)
 
     await session.patch(
       'index.js',