Merge "[Ongoing call] Don't show the time if the notification's `when` value...

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

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

Change-Id: Ic73c5a4a8b6c359c8cdd07b0516d26602a61a176