Bump django-csp from 3.8 to 4.0 (#1085)

Bumps [django-csp](https://github.com/mozilla/django-csp) from 3.8 to 4.0.
- [Release notes](https://github.com/mozilla/django-csp/releases)
- [Changelog](https://github.com/mozilla/django-csp/blob/main/CHANGES.md)
- [Commits](mozilla/django-csp@3.8...v4.0)

---
updated-dependencies:
- dependency-name: django-csp
  dependency-version: '4.0'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

testproject/requirements.txt

@@ -1,5 +1,5 @@
 pytz==2025.2
-django-csp==3.8
+django-csp==4.0
 boto3==1.38.3
 django-formtools==2.5.1
 django-storages==1.14.6