Versioning code in `do_versions_after_linking_260` inserted new group input
and output nodes. And (reasonably?) expected sockets to exist on those nodes.
However, `nodeAddStaticNode` did not initialize sockets on nodes with that use
`declare_dynamic` yet. This patch changes it so that `declare_dynamic` is used
in more places, which caused issues during file loading when node groups are
updated in somewhat arbitrary order (not in an order that is based on which
groups use which).
Differential Revision: https://developer.blender.org/D17183
2a19810f97