Stop differentiating between left and right ALT

For user the behaviour seems like it's just the same button so we should display it accordingly.

Fixes: 323187810
Test: check sticky key indicator with left and right alt, it should display only "ALT"
Flag: ACONFIG com.android.hardware.input.keyboard_a11y_sticky_keys_flag TRUNKFOOD
Change-Id: I5d8021e101304226bc4f9a8d537f6e029f4066ce