Update documentation for experimental Playwright test mode + msw v2 (#71841)
Next.js 15 updated `msw` from 1.3.0 to 2.3.0
(https://github.com/vercel/next.js/pull/66351), this PR updates the
example in the experimental Playwright test mode documentation to
reflect this.
Additionally:
- Added catch-all passthrough route to example.
- Fixed issue in the example with how `mswHandlers` was used
(https://playwright.dev/docs/test-fixtures#fixtures-options)
Relevant discussions:
https://github.com/vercel/next.js/issues/71832
https://github.com/vercel/next.js/discussions/71330
---------
Co-authored-by: JJ Kasper <jj@jjsweb.site>