feat(files): support nested actions

[skjnldsv]

• Fix Add API for FileAction submenu actions #39718
• Needs feat: support nested actions nextcloud-libraries/nextcloud-files#814
• Needs 3.0.0-beta.27 nextcloud-libraries/nextcloud-files#823
• Needs 8.0.0-beta.10 nextcloud-libraries/nextcloud-vue#4754

[skjnldsv]

@Pytal please review the logic!

Especially the condition on where a reminder is shown or not, as I wasn't part of the original discussions! I used your services, so I think it should be good.
But here are a few questions to be safe

1. Is it normal that depending on the time of day, only some options are visible?
2. Is this feature enabled for all nodes, no matter what they are and what permissions they have? (folder/files, etc etc)

[Pytal]

1. Is it normal that depending on the time of day, only some options are visible?

Yes this is by design

2. Is this feature enabled for all nodes, no matter what they are and what permissions they have? (folder/files, etc etc)

Yes, if you can see (read) the file then you should be able to set a reminder on it

[susnux]

The focus handling does not work properly:
If you click (keyboard) on "set reminder" the submenu opens but the focus is not set on the submenu's first element.

Also if you click the back button the first submenu is reopend, but the focus is not on the "set reminder" entry.

In both cases the focus is on some random non visible element.

[Pytal]

Since the presence of the action should be evaluated ideally on click instead of on script execution I think the FileAction enabled callback needs to be set to something like () => Boolean(getDateTime(option.dateTimePreset)) to be more reactive

[skjnldsv]

Can be improved later

[susnux]

🐘 a11y in follow up?