Deprecate unused metrics

PROVISIONING_TRAMPOLINE_ACTIVITY_TIME_MS
PROVISIONING_POST_ENCRYPTION_ACTIVITY_TIME_MS
PROVISIONING_FINALIZATION_ACTIVITY_TIME_MS

These metrics are meant to measure intermediate screens, e.g.
screens which finish() in onCreate. It does not make sense to
measure the time they have been shown.

Test: compiled
Fixes: 135599174
Change-Id: I14d4f0b9fb5d70cfaeb386eb14348c0cc499113a