Fix pages in workflow status showing up as "live + draft"

[laymonage]

Fixes #10925

It turns out the fix is literally one liner, changing the GenericRelation to use content_type instead of base_content_type. However, that depends on whether we're working with a specific queryset or the base Page queryset. I opted to have two GenericRelations instead so that we can use prefetch_workflow_states() with either, and it will pick the correct relation accordingly.

And yeah, it turns out prefetching GenericRelations with a custom queryset still works fine on Django < 5.0. The one that needs Django >= 5.0 is prefetching GenericForeignKeys, because the result can be of different models.

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?

Please describe additional details for testing this change.

With bakerydemo, the issue in #10925 shouldn't occur anymore.

Footnotes

1. Development Testing ↩

[squash-labs]

Manage this branch in Squash

Test this branch here: https://laymonagefix-moderation-status-quzo6.squash.io

[gasman]

Looks good to me!

[gasman]

Merged in ad6688f