Allow ModelViewSet to be used for models with non-integer primary keys

[laymonage]

Similar fixes to #4166 and #7208.

To test:

I don't have a bakerydemo branch for this, but I've been using the testapp. You can configure this in the following:

• Edit DEBUG in wagtail/test/settings.py to True (would love to change this in a separate PR)
• Run:

  cd wagtail/test
  DATABASE_NAME=wagtail.db python manage.py migrate
  DATABASE_NAME=wagtail.db python manage.py createcachetable
  DATABASE_NAME=wagtail.db python manage.py loaddata test.json # optional
  DATABASE_NAME=wagtail.db python manage.py loaddata test_specific.json # optional
  DATABASE_NAME=wagtail.db python manage.py createsuperuser
  DATABASE_NAME=wagtail.db python manage.py runserver

The server will run with the testapp configured. You can then use the Feature Complete Toy model to test the URLs. For testing the legacy redirects in ModelViewSet, you need to use a primary key string that's also a valid integer, as the old URL patterns use <int:pk>.

Please check the following:

• Do the tests still pass?¹
• Does the code comply with the style guide?
  • Run make lint from the Wagtail root.
• For Python changes: Have you added tests to cover the new/fixed behaviour?
• For new features: Has the documentation been updated accordingly?

Footnotes

1. Development Testing ↩

[squash-labs]

Manage this branch in Squash

Test this branch here: https://laymonagemodelviewset-non-inte-levys.squash.io

[laymonage]

Not sure if this should be in a new migration, I don't think it's worth it because the testapp is pretty much ephemeral and not intended to be long-lived. Properly migrating this would need more than one migration (to add the new field, populate, remove the old one).

We could start with a new model, but I intended this model to be the main model to test all ModelViewSet features (hence "feature complete").

[gasman]

All looks good to me!