Previous approach was using non-evaluated meshes to find the closest edge from a face index retrieved from the selection buffer.
This can fail though if the mesh is deformed or even altered to not have the same indices anymore (e.g. generating/masking modifiers).
In order to make this work, added `ED_mesh_pick_edge` which switches the selection context to edges directly
and picks from those. No need to map anything back and forth between original and evaluated, the selection buffer contains the original indices already.
Further logic (following the face loop) is untouched (and happens on the original geometry which is fine)
Should go into 4.2 LTS as well
Pull Request: https://projects.blender.org/blender/blender/pulls/132803
eecf5787c1