Publish dialogs show a single culture for invariant documents

[kjac]

Which Umbraco version are you using? (Please write the exact version, example: 10.1.0)

15.1

Bug summary

The publishing dialogs (schedule for publish, publish with descendants) show a single language for invariant documents on multi-language sites:

It seems a little weird - either all languages should be shown, since language variant documents can exist below invariant ones, or otherwise no languages should be shown.

For reference, V13 does not show any languages:

Specifics

No response

Steps to reproduce

1. Setup multiple languages.
2. Create an invariant document.
3. Check the publishing dialogs, as shown above 😄

Expected result / actual result

No response

[kjac]

Possibly related to #17793