Use receiving window's input channel token for transferring drag gesture

Previously, it was necessary to provide the entire input channel in
order to transfer the touch gesture for drag.

This is actually fine because in the case of the drag window, the
inputchannel is stored inside system_server, so we do have direct access
to it.

Still, to make this API more flexible and to better align it to the
"from/to" style, let's convert this to use the input channel token. This
should also reduce the need to duplicate the input channel's fd if we
ever make this a binder call in the future.

Bug: 323450804
Test: atest android.view.surfacecontrol.cts.SurfaceControlViewHostTests
Test: atest WmTests:com.android.server.wm.DragDropControllerTests
Flag: EXEMPT refactor
Change-Id: I5639f25462e283f49af6d7801a98818022ac798b