Restricting and unrestricting access to a table results in the DB-level permission still being "Granular"

[noahmoss]

Describe the bug
If you restrict data access to a single table in a database, and then change it back to unrestricted, the data access level in the UI for the entire database will display as "Granular" even though access to all the tables is unrestricted.

To Reproduce
Steps to reproduce the behavior:

1. On a fresh instance of Metabase, go Admin -> Permissions
2. Click on 'All Users'
3. Click on 'Sample Database'
4. Change the data access for a single table to 'No self-service', and save
5. Change the data access for that table back to 'Unrestricted', and save
6. Click on 'Sample Database' again. See that the data access is displayed as 'Granular', even though all tables have unrestricted access.

Expected behavior
Data access to the DB should go back to 'Unrestricted'

Information about your Metabase Installation:
Current master

Severity
Minor, but probably blocking some work for an upcoming project so serious in that regard.

[noahmoss]

Seems like this is the same as #16253, closing in favor of that

[flamber]

Quite sure it's not a duplicate of #16253, since that's specifically about Sandboxing. Sounds a lot more like #17764

[noahmoss]

It's not a duplicate of #16253 from a user point of view but I'm pretty sure it has the same root cause on the backend.

@camsaul said he can fix that one quickly, so I'll reopen this until we verify that fixing that issue fixes this one as well.

[noahmoss]

@alxnddr This is actually a backend bug (i.e. it should be replacing the individual permission paths for each table with a general one for the DB). As far as I can tell, the frontend will do the right thing when the backend is fixed.

[noahmoss]

@alxnddr I take it back, this does seem to be a frontend issue. On the second request, the frontend is sending a graph that looks like this (in part):

        "data": {
          "schemas": {
            "PUBLIC": {
              "1": "all",
              "2": "all",
              "3": "all",
              "4": "all"
            }
          }
        }

It should be sending a graph that looks like this, if it knows that all tables have unrestricted access:

        "data": {
          "schemas": "all"
        }