Bump werkzeug from 3.1.4 to 3.1.5 in /lambdas/ack_backend (#1127)

Bumps [werkzeug](https://github.com/pallets/werkzeug) from 3.1.4 to 3.1.5.
- [Release notes](https://github.com/pallets/werkzeug/releases)
- [Changelog](https://github.com/pallets/werkzeug/blob/main/CHANGES.rst)
- [Commits](pallets/werkzeug@3.1.4...3.1.5)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Akinola Olutola <akinola.olutola1@nhs.net>
Co-authored-by: Daniel Yip <daniel.yip4@nhs.net>

Author: 3 people