Merge "[Ongoing call] Don't show the time if the notification's `when` value isn't valid." into sc-dev am: 3ad556f6 am: dacdfd7b am: 5a58e74e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15177730

Change-Id: I2e0b023b609ab15d7596139bf6af16308f359571