closes: https://github.com/coder/internal/issues/858
Similar to https://github.com/coder/coder/pull/19375, this one uses
system permissions for fetching actual user and group data.
Modifies the `workspaces_expanded` view to fetch the required data; this way it's made available to all code paths that make use of it.
Also fixes a bug in a test helper function that can result in `null` being saved to the DB for `user_acl` or `group_acl` and break tests; a defensive check constraint that prevents this is worth a PR, e.g:
`ALTER TABLE workspaces
ADD CONSTRAINT group_acl_is_object CHECK (jsonb_typeof(group_acl) = 'object');`
Also adds missing `OwnerName` in `ConvertWorkspaceRows`.