Make InputDispatcher logs available dynamically

This will allow us to turn on these logs without having to rebuild and
make it easier to debug.

Bug: 211915757
Test: adb shell setprop log.tag.InputDispatcherFocus DEBUG
Test: check that the logs get enabled
Change-Id: Ie1b1445e52b71c373933d085367d74bf568b5462
(cherry picked from commit f2f827c5)