Adding nodes via `NodeAddOperator` could fail if the node's poll fails
in `rna_NodeTree_node_new`. Examples are trying to add a RenderLayers
node or a Cryptomatte node to a nodegroup.
Now except the python error and use blender error reporting only instead
of throwing full python stacktraces at the user.
Differential Revision: https://developer.blender.org/D14584
4aac251b42