A followup for 5e7f3e5c84.
Make the NOD_static_types.h file less important by moving `enum_name_legacy`
to be defined in the register function of every node. This helps our gradual transition
away from this file.
Also add a fallback to the node idname so that newly added nodes no longer need
to define the string value.
Pull Request: https://projects.blender.org/blender/blender/pulls/132131
b43e2168e3