build(deps): update mistune requirement in /server

Updates the requirements on [mistune](https://github.com/lepture/mistune) to permit the latest version.
- [Release notes](https://github.com/lepture/mistune/releases)
- [Changelog](https://github.com/lepture/mistune/blob/main/docs/changes.rst)
- [Commits](lepture/mistune@v3.3.0...v3.3.2)

---
updated-dependencies:
- dependency-name: mistune
  dependency-version: 3.3.2
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

server/requirements.txt

@@ -17,4 +17,4 @@ packaging==26.2
 tzdata  # IANA timezone database for zoneinfo on slim containers without system tzdata
 werkzeug>=3.1.8 # not directly required, pinned by Snyk to avoid a vulnerability
 zipp>=4.1.0 # not directly required, pinned by Snyk to avoid a vulnerability
-mistune>=3.3.0 # not directly required, pinned by Snyk to avoid a vulnerability
+mistune>=3.3.2 # not directly required, pinned by Snyk to avoid a vulnerability