chore(deps): bump django-polymorphic from 4.6.0 to 4.8.0 (#14060)

Bumps [django-polymorphic](https://github.com/jazzband/django-polymorphic) from 4.6.0 to 4.8.0.
- [Release notes](https://github.com/jazzband/django-polymorphic/releases)
- [Changelog](https://github.com/jazzband/django-polymorphic/blob/master/docs/changelog.rst)
- [Commits](django-commons/django-polymorphic@v4.6.0...v4.8.0)

---
updated-dependencies:
- dependency-name: django-polymorphic
  dependency-version: 4.8.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements.txt

@@ -13,7 +13,7 @@ django-environ==0.12.0
 django-filter==25.2
 django-imagekit==6.0.0
 django-multiselectfield==1.0.1
-django-polymorphic==4.6.0
+django-polymorphic==4.8.0
 django-crispy-forms==2.5
 django_extensions==4.1
 django-slack==5.19.0