menupage_panel does not include PrivacyModalPanel

[bmihelac]

Privacy panel missing in settings tab for MenuPage and subclasses.

menupage_settings_panels is defined in https://github.com/rkhleics/wagtailmenus/blob/master/wagtailmenus/panels.py#L100-L107 and clearly it does not have PrivacyModalPanel.

As far as I can see PrivacyModalPanel is added to wagtail in v2.10:

wagtail/wagtail@84f3265

For the reference, missing panel is marked on the image:

[benfroelich]

Though PrivacyPanel is no longer added directly to settings_panels since this commit wagtail/wagtail@0693eed#diff-b15877f11b1b7e35b3dce47e57f8aff6dccac9a02f3f94caf860a5e51fd48360L1072, I am raising the same underlying issue here as it affects other panel contents.