Release IllustrationVideoView in onStop. DO NOT MERGE

Based on the view's visibility, release or reattach
IllustrationVideoView as soon as it becomes invisible to avoid
media player resources being held on for a long time, and to avoid
multiple video views being released all at once at the end of setup
wizard.

Test: ./gradlew test connectedAndroidTest
Bug: 78360819
Bug: 117581782
Change-Id: Idc5af901122562d12ff3d7b1ee46012b7a60cf25
(cherry picked from commit 6ffb792f)