This adds a simple `compute_context_for_edittree` function that returns the
"active" compute context for the given node editor. This is used in various
places, but previously one had to construct the compute context in multiple
steps (first find the root context (modifier/operator), then handle the tree
path). Since the edittree already has a specific active context, there should be
an easy way to retrieve that.
This also adds a few extra check that avoid redundant work that was done before.
Pull Request: https://projects.blender.org/blender/blender/pulls/137525
411d4204f6