⬆️ Bump marshmallow from 3.23.2 to 3.24.0 in /backend

Bumps [marshmallow](https://github.com/marshmallow-code/marshmallow) from 3.23.2 to 3.24.0.
- [Changelog](https://github.com/marshmallow-code/marshmallow/blob/dev/CHANGELOG.rst)
- [Commits](marshmallow-code/marshmallow@3.23.2...3.24.0)

---
updated-dependencies:
- dependency-name: marshmallow
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

backend/requirements.txt

@@ -22,7 +22,7 @@ httpcore==1.0.7 ; python_version >= "3.10" and python_version < "4.0"
 httpx==0.28.1 ; python_version >= "3.10" and python_version < "4.0"
 idna==3.10 ; python_version >= "3.10" and python_version < "4.0"
 iniconfig==2.0.0 ; python_version >= "3.10" and python_version < "4.0"
-marshmallow==3.23.2 ; python_version >= "3.10" and python_version < "4.0"
+marshmallow==3.24.0 ; python_version >= "3.10" and python_version < "4.0"
 multidict==6.1.0 ; python_version >= "3.10" and python_version < "4.0"
 packaging==24.2 ; python_version >= "3.10" and python_version < "4.0"
 passlib[bycrypt]==1.7.4 ; python_version >= "3.10" and python_version < "4.0"