Blender Git Loki

Cleanup: Remove operator context override for drop-box operators

Drop-boxes should act on the context determined through the exact cursor
location. There should be no need to override that, basically by the
nature of how drop-boxes work.
So Campbell and I agreed on removing this.

If we wanted to support it, we'd have to restore the operator context
when drawing drop-boxes, see
https://developer.blender.org/T92501#1247581.