Restricting UiModeManager#setNightMode

Apps have been trying to set their night modes by calling this
function but they end up toggling the system-wide UiMode.

From now on, an error message will be logged if the app doesn't
hold the right permission.

Change-Id: Ie62c870b84190a62321a05a007cd2bf3dc9851f8
Fixes: 113605757
Test: manual. open app that tries to trigger night mode