DO NOT MERGE: startop: Downgrade EventSequenceValidator to warning.

Downgrade EventSequenceValidator into warnings for rvc-dev since the C++ side
will already handle bad state transitions from ActivityMetricsLogger.

Only for rvc-dev because we'll want to properly fix this for S.

Bug: 152322073
Test: build
Change-Id: Idf7a68436c2d60b123e0e6e58dc098b62aa11e80