www/py-strawberry-graphql-django: Update to 0.47.1

• Belatedly add CONFLICTS_INSTALL while I'm here, because the port has now also had www/py-dj50-strawberry-graphql-django as Django 5.0 counterpart since 9dcfcfc7df21.

Changelog since 46.1:

https://github.com/strawberry-graphql/strawberry-django/compare/v0.46.1...v0.47.1