Update celery requirement from ==5.4.* to ==5.5.* in /server (#346)

Updates the requirements on [celery](https://github.com/celery/celery) to permit the latest version.
- [Release notes](https://github.com/celery/celery/releases)
- [Changelog](https://github.com/celery/celery/blob/main/Changelog.rst)
- [Commits](celery/celery@v5.4.0rc1...v5.5.2)

---
updated-dependencies:
- dependency-name: celery
  dependency-version: 5.5.2
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

server/requirements.txt

@@ -2,7 +2,7 @@
 aiofile==3.9.*
 aiohttp==3.11.18
 beautifulsoup4==4.12.*
-celery==5.4.*
+celery==5.5.*
 channels==4.2.*
 channels_redis==4.2.*
 Django==4.2.*