Prevent adding assets to "all" if user has only privilege to see some collections.

[Sebobo]

Description

Currently when a user adds an asset to the virtual "all" collection, meaning no collection, but can only see a certain set of collections, the asset is not visible to them after upload.

Steps to Reproduce

1. Restrict role to only see one collection
2. Upload asset to "all"

Expected behavior

The asset goes to their first accessible collection or they cannot select "all".

Actual behavior

The asset disappears

[Sebobo]

@lorenzulrich do you think we should hide/disable the "All" collection or change its behaviour to match the users privileges?

[lorenzulrich]

I'm not sure if there is a "one size fits all approach" to this.

Some considerations

• When I create a new multi-site website with one asset collection per site and respective privileges, even as an admin I might not want to have the virtual "All" collection because I might add assets to places where my editors couldn't see them.
• However, when I'm changing an existing single-site website to a multi-site, I need to see "All" assets (basically such without an asset collection) so I can "move" them to the appropriate place.

Currently, I'd be in favour of having a privilege for the "All" entry point so I could leave it on for an admin if necessary, but deactivate it for editors.