Access a shared dashboard with me without having access to the collection

[sebbousquet]

If a user has shared a dashboard in a group, the dashboard appears in the list of available dashboards for all users in that group without checking whether those users can access the collection used in the dashboard.

[alainbodiguel]

Proposal from SG: we should prevent the sharing when the group does not have enough permissions on required collections.

The hub should check that the collections of the dashboad are in the allowed collections of the targeted group (requires a new endpoint to get a map of groups/column-filters).
Because persistence cannot do it (does not know what it stores).