ActivityMetricsLogger: Fix cold launches treated incorrectly as invalid transitions

In some cases where the process is killed and the activity is launched, its start result will be
START_TASK_TO_FRONT if its TaskRecord already exists. In this case the launch should be treated
as a COLD launch since the process will be created.

Bug: 130401938
Test: atest ActivityMetricsLoggerTests
Change-Id: I2841fe198d189be692c38f94829604bd1e4aa3b5