Remove old power menu code

The new power menu lite replaces this version of the power menu, so
we should clean up the unused code

Bug: 179674461
Test: builds; atest com.android.systemui.globalactions
Change-Id: I8e21edf45d87a87b8979fd8ee8b6bb13e277e0d8
(cherry picked from commit e63fd7e224dd0e2541244d102f910a592c90f804)
3 files changed