🧰 Task

All the providers in napari/_app_model/injection/_providers.py depend on Qt. _provide_viewer uses _QtMainWindow.current_viewer() which returns None on import error. The other 2 providers both rely on _provide_viewer.

see: #4991 (comment)

All 3 providers should be moved to napari/_qt/_qapp_model/injection/_qproviders.py

Note this depends on #4991 being merged first.