For the `plane_depth` of type `PLACE_DEPTH_SURFACE` to take effect, a `snap_context` is needed.
But, even if a temporary `snap_context` was created for `plane_orient == PLACE_ORIENT_SURFACE`,
this context was not used for `plane_depth`.
So, use a temporary `snap_context` for `PLACE_DEPTH_SURFACE` (as it is done for `PLACE_ORIENT_SURFACE`).
Differential Revision: https://developer.blender.org/D9345
Differential Revision: https://developer.blender.org/D9435