with owner a blocking alert on Write may be too much

[bourgeoa]

https://github.com/solid/solid-ui/pull/398 introduced in the sharing-pane :
. ask for confirmation if there is no Control access (no "Owners")
. display an alert if there is no Write access (no "Owners" and no "Editors") : the resource cannot be deleted and the ACL resource cannot be accessed.

With implementation of owner in NSS Write should not be needed to avoid a locking mechanism.

Proposal : replace blocking alert by asking confirmation that the user is aware that there is no Write on resources depending from that acl.