Simple pass-through TimeDetectorService

This is sufficient to wire up time detection from telephony
to the new service without breaking time detection.

This cherry-pick contains a small change: to use
SystemClock.elapsedRealtime() instead of the newer
SystemClock.elapsedRealtimeClock() with Clock.millis().

Bug: 78217059
Test: atest FrameworksServicesTests:com.android.server.timedetector
Test: atest FrameworksCoreTests:android.util.TimestampedValueTest
Merged-In: Id7175878dc22e5272c31f3e478af4b0e4183b62b
Change-Id: Id7175878dc22e5272c31f3e478af4b0e4183b62b
(cherry picked from commit 24836bfb)