In the data-block selectors in the node editor and the header,
apply a few rules to increase the separation between tool and
modifier node groups.
1. The modifier accepts non-asset groups or assets marked
as modifiers (created in the modifier context). Tool node groups
cannot be used by modifiers.
2. The tool context can only edit node group assets marked as tools
(created in the tool context).
When switching contexts, the node group is cleared if the state would
be invalid. The tool node group is still stored in the editor's "root node
tree" property. Since it isn't retrieved from the context, the pin button
is useless, so it isn't displayed in the tool mode.
See #101778, #111526.
Pull Request: https://projects.blender.org/blender/blender/pulls/112389
1c51f74cb4