Add Generics to `DropResult` type

[Mnigos]

Description

Making DropResult a generic type to specify type of droppableId

Right now I have to assert the type.

  async function onDragEng({ source, destination, draggableId }: DropResult) {
    if (!destination) return

    if (destination.droppableId === source.droppableId) {
      reorderTasks(
        source.droppableId as BoardKey,
        source.index,
        destination.index
      )
    }
  }

I would like to specify type for droppableId in DropResult type argument

  async function onDragEng({ source, destination, draggableId }: DropResult<BoardKey>) {
    if (!destination) return

    if (destination.droppableId === source.droppableId) {
      reorderTasks(
        source.droppableId,
        source.index,
        destination.index
      )
    }
  }