See #101778
Remove the requirement of restarting Blender to refresh the
extended 3D view menus for node group changes. Also avoid
rebuilding the tree of relevant assets and catalogs on every
redraw, since parsing asset libraries, etc. could become more
expensive than we want. Those two goals combined mean we
have to be more rigorous in how we invalidate the cached
catalog tree.
The first main change required is to clear the tree as asset libraries
are being read, similar to other dynamic asset menus. This is done
with a 3D view header listener rather than a menu listener in this case.
However, that isn't enough, because there is an issue with the asset
system where the "all" library isn't updated when the current file library
changes. The solution is to explicitly rebuild the "all" library's catalogs
when other asset libraries are changed.
The other necessity for dynamic updates is clearing the catalog tree
to be rebuilt when the node group "asset traits" are changed. This is
done with a new notifier type (with the goal of being a bit selective
about when we re-read assets). This _also_ requires running the
"presave" callback that builds asset metadata when updating the
property. Otherwise saving the file and sending the notifier is
necessary, which is too confusing.
Pull Request: https://projects.blender.org/blender/blender/pulls/112166