Bump python-multipart from 0.0.10 to 0.0.18 in /app/backend

Bumps [python-multipart](https://github.com/Kludex/python-multipart) from 0.0.10 to 0.0.18.
- [Release notes](https://github.com/Kludex/python-multipart/releases)
- [Changelog](https://github.com/Kludex/python-multipart/blob/master/CHANGELOG.md)
- [Commits](Kludex/python-multipart@0.0.10...0.0.18)

---
updated-dependencies:
- dependency-name: python-multipart
  dependency-type: direct:production
...

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

app/backend/requirements.txt

@@ -20,7 +20,7 @@ pandas==2.2.3
 Pillow==10.4.0
 pytest==8.3.3
 python-dotenv==1.0.1
-python-multipart==0.0.10
+python-multipart==0.0.18
 tabulate==0.9.0
 tiktoken==0.7.0
 uvicorn==0.30.6