Required because the lights need to be turned off late in boot
(e.x. during fsck for disk health), and before, blank_screen
accessing light encountered a race condition where if it didn't
get scheduled before all of the processes which were getting
shutdown were getting killed, the screen wouldn't blank.
Bug: 74976325
Test: adjusting brightness continues to work
Test: screen blanks during shutdown at the correct time
including when an artificial 5s delay is inserted when
the phone normally fscks (which can also be quick)
Change-Id: I57ebc11d7ecf57ee327c681455712f4b53de6fd3
So that init knows how to start it and to provide
an example of how to specify interfaces since there
are no lazy starting services on Pixel yet.
In order to make lights a lazy service, it would also
have to be marked as 'oneshot'.
Test: manually using Light as a lazy service
Bug: 64678982
Change-Id: I846a7e2d9545b42af9b985adb74883bda1b8c355
