[SB][Chips] Fix up the ShortTimeDelta Compose Chips.

Two changes:
1) I only just realized that the ShortTimeDelta time is in
   currentTimeMillis units instead of elapsedRealtimeUnits, so I updated
   the Compose view to use currentTimeMillis as the baseline.
2) Update TimeRemainingState to use the right duration from the outset
   so that the chip doesn't flash "now" for a brief moment.

Fixes: 400784488
Bug: 372657935
Flag: com.android.systemui.status_bar_chips_modernization
Test: Trigger notif chip with time in the future -> verify chip shows
the time delta correctly. Verify with ChipsModernization both off and on

Change-Id: Id1729675205b7add3275527f94999b25cda5c388