cherry-pick(#29271): Revert "chore: remove fake error from expect calls (#28112)" (#29296)

This PR cherry-picks the following commits:

- 622153db18

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

packages/playwright-core/src/server/dispatchers/frameDispatcher.ts

@@ -262,6 +262,8 @@ export class FrameDispatcher extends Dispatcher<Frame, channels.FrameChannel, Br
     const result = await this._frame.expect(metadata, params.selector, { ...params, expectedValue });
     if (result.received !== undefined)
       result.received = serializeResult(result.received);
+    if (result.matches === params.isNot)
+      metadata.error = { error: { name: 'Expect', message: 'Expect failed' } };
     return result;
   }
 }