Bump django from 5.0.2 to 5.1.14 in /backend

Bumps [django](https://github.com/django/django) from 5.0.2 to 5.1.14.
- [Commits](django/django@5.0.2...5.1.14)

---
updated-dependencies:
- dependency-name: django
  dependency-version: 5.1.14
  dependency-type: direct:production
...

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

Author: dependabot[bot]

backend/Pipfile

@@ -24,7 +24,7 @@ pandas = "*"
 html5lib = "*"
 psycopg2 = "*"
 sentry-sdk = "*"
-django = "==5.0.2"
+django = "==5.1.14"
 django-cors-headers = "*"
 pyyaml = "*"
 uritemplate = "*"