When collecting operators for the operator cheatsheet (Help menu),
`node.interface_item_new` gave an error because its property
`active_item` could not gather items. This happened because `context`
was unavailable to its `get_items` method at that time.
This commit refactors the method to return early in case the context is not
found.
Pull Request: https://projects.blender.org/blender/blender/pulls/145930
3611b8a592