feat: add sharing info to /workspaces endpoint (#21049)

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`.

coderd/database/modelqueries.go

@@ -323,6 +323,8 @@ func (q *sqlQuerier) GetAuthorizedWorkspaces(ctx context.Context, arg GetWorkspa
 			&i.TemplateIcon,
 			&i.TemplateDescription,
 			&i.TaskID,
+			&i.GroupACLDisplayInfo,
+			&i.UserACLDisplayInfo,
 			&i.TemplateVersionID,
 			&i.TemplateVersionName,
 			&i.LatestBuildCompletedAt,