Add onKeyEvent, to support KEYCODE_HOME

- Also added displayId to onBackEvent

Bug: 381339822
Flag: com.android.launcher3.home_button_uses_keycode_home
Test: Manual, OverviewCommandHelperTest
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:622a882e1f17d108a336ecfd3e4eb7aa9707f1e6)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:7ff1e38f7d707d860d9bc7557056050c4aaf4025)
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:ec15cee125b81d66eee0a24682b223c1f8713833
Merged-In: I55e2ee7adfa40c9d8f289a2b4c76aa12f80e78c3
Change-Id: I55e2ee7adfa40c9d8f289a2b4c76aa12f80e78c3