Blender Git Loki

Fix T89851: Geometry nodes: wrongly detected "Node group has unidentified
nodes or sockets" error

rBfe22635bf664 introduced a utility to check for this (but it was always
returning true).

This wasnt a problem in master (since it is unused there), but in the
2.93 branch, this utility is actually used and the error results in all
geometry nodetrees to appear with the "Node group has unidentified nodes
or sockets" message (and being unusable).

Now return false in has_undefined_nodes_or_sockets if all nodes and
sockets have been successfully checked.

This commit then needs to end up in the 2.93 branch.

Maniphest Tasks: T89851

Differential Revision: https://developer.blender.org/D11911