Update PreRebootStatsReporter api level

With the upcoming command line tools update in ag/34989485,
there are several NewApi lint errors. This cl updates the api
level of PreRebootStatsReporter so that no baseline file is needed
for landing the new lint executable.

Test: m lint-check with topic "lint-upgrade"
Bug: 452688941
Bug: 441794572

Flag: NONE update lint baseline
Change-Id: Ib315225a628b6eb801cf40ecc93230471390f1e6