R1:2260738de9e0

When dragging nodes between different columns on an ordered board, don't reorder them by making secondary edits

Summary:
Ref T10334. When a workboard is ordered by priority, dragging from column "A" to a particular place in column "B" currently means "move this task to column B, and adjust its priority so that it naturally sorts into the location under my mouse cursor".

Users frequently find this confusing / undesirable.

To begin improving this, make "drag from column A to column B" and "drag from…