Tabs are showing even when there are no visible panels inside

Issue Summary

In wagtail 3.0 a tab in the admin UI is shown even if it has no visible panels or fields (e.g. because of lacking user permissions).

Steps to Reproduce

1. In the bakery demo, update the blog model (or any model) with the following settings_panels

    settings_panels = [
        FieldPanel("go_live_at", permission='superuser')
    ]

1. As superuser, confirm you can view the settings tab and see one field
2. Create a user that does not have superuser (admin) permissions
3. In a new incognito window, sign in as the non-superuser
4. Load any blog page
5. Expected: The settings tab should not show at all
6. Actual: The settings tab shows but no fields are visible within it

Screenshot

User does not have permissions to see the settings panel fields and instead of the tab not showing at all, it shows but is blank inside.

Additional context

• This is because wagtailadmin/panels/tabbed_interface.html renders child in self.children instead of child in self.visible_children.
• Maybe there is a good reason for this implementation but from a editor perspective it looks like something’s wrong…

Technical details

• Python version: 3.9.
• Django version: 4.0.
• Wagtail version: 3.0.

[katzmo]

Thank you!!!

[lb-]

Cherry picked to 3.0 branch https://github.com/wagtail/wagtail/commit/6b16de6c7b1cb251acc61fd2d7a0e8ad885f0356