Removed the UI for the callout card feature flag
Removed the UI for the callout card feature flag

no issue

- The feature flag was removed in https://github.com/TryGhost/Admin/commit/5cf00b8a68c9ec057ebeed6a30b5aae64f31917d
- The UI was remaining, although it wasn't working

TryGhost/Ghost-Admin,TryGhost/Ghost-Admin