Settings: add never sleep screen mode (2/2)

Thanks to kufikugel

https://github.com/temasek/android_packages_apps_Settings/commit/277f3abac0e3f591e5939b90c581551e18ddff26
(cherry picked from commit 58de40f9fb279aba4d84ea776185e54662e15907)
(cherry picked from commit b5cff9705de3f30d4571886bdef8295a1fdecb07)