This happens because blender 4.3 only knows about GPv3 IDs, and
therefore stores a reference to a directly linked GPv2 obdata as a GPv3
one, which cannot be found again on next file load in the GPv2 library.
The idea of this fix is, if the looup of a idcode+idname fails, to also
search for the same name but with an older, deprecated ID code.
