The new users / sites setting we added as part of this release. We should only show the system summary items and quick links when those features are enabled. Quick links will now show an empty widget when both users and sites admin is disabled but that's fine for now as it's very much edge case. The widget itself could be always removed.
Another issue this PR fixes is that in CoreAdminHome there were 2 widgets we didn't check if another plugin maybe disabled them and where still showing them