Fix missing Input when letterbox surfaces are recreated

In the case the letterbox surfaces are recreated after a applySurfaceChanges
the InputEventReceiver needs to be reinitialized.

This happens, for instance, when we update the rounded corners size
using the adb command "adb shell wm set-letterbox-style --cornerRadius <value>"

Flag: EXEMPT Bug fixing
Bug: 308914914
Test: atest WmTests:LetterboxTest
Test: atest WmTests:LetterboxAttachInputTest
Test: follow steps on the bug description

Change-Id: Ibbf6da5f5fe018d292ee6a8251831f5ede08808f