Release IllustrationVideoView in onStop

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
Change-Id: Idc5af901122562d12ff3d7b1ee46012b7a60cf25