Prevent keyboards from being recognized as a stylus

We are getting reports of keyboards and other peripherals being
misconfigured as a stylus, because they report support for stylus
buttons.

To eliminate some of these misconfigurations, prevent anything detected
as a alphabetical keyboard from being categorized as a stylus.

Bug: 293996865
Test: None
Change-Id: I3f071d2ac6a2b70abc1130b4d5df1509452bb63b
(cherry picked from commit 3c28b945)