Allows propagating launch cookies to next launching visible activity

The launch cookie failed to pass to the next launching activity because
the metrics logger was aborted early while the next launching activity
was already visible.

Bug: 433389861
Test: ActivityMetricsLaunchObserverTests
Flag: EXEMPT bugfix
Change-Id: Icbfa8a6b1b7a107ddc64c6d34e10ff794a82800b