## Summary
- System objects with valid views were incorrectly hidden in the View >
System objects picker
- The system picker page used a different filter (`view.key !==
ViewKey.INDEX`) than the parent page
(`isViewDisplayableInNavigationMenu`), causing a mismatch where the
"System objects" link was visible but clicking it showed an empty list
- Aligned filtering in `SidePanelNewSidebarItemViewSystemPickerSubPage`
to use `isViewDisplayableInNavigationMenu` and exclude views already in
the workspace, consistent with the non-system picker page
