Blender Git Loki

Fix T87357: Missing update after removing socket

The CoW copy of the node group was not updated correctly after it
changed. Arguably, tagging the node tree could also be part of
`ntreeUpdateTree` (which needs to be called after changes to the
node tree anyway). However, there are many instances where the
depsgraph is tagged explicitly after `ntreeUpdateTree` is called,
so it should be fine here as well. This is similar to what is done
in `snode_dag_update`.

Differential Revision: https://developer.blender.org/D11342