Use input token in PointerCaptureRequest

Instead of sending boolean to indicate the capture state,
InputDispatcher now sends an input window token that requests a
pointer capture or nullptr otherwise.

Bug: 259346762
Bug: 301628662
Test: android.view.cts.PointerCaptureTest WindowFocusTests#testPointerCapture
Change-Id: Ie0824a11994541d391dbd2cf1ea3dcf0689be52a