Add time until Night Light is on/off as secondary label

Added secondary label text for Night Light.

2 modes with 2 text options:
1) Twilight - until sunrise OR on at sunset
2) Custom - until <time> OR on at <time>

Test: Visually tested - tried all 4 variations + manual toggle + updates
Bug:69973398
Change-Id: I5d0d213b470608b7dfa9d6cce0c33be1365e10a0