Revert "Make RollbackPackageHealthObserver observe apk-in-apex"

This reverts commit d56ce0003926fd9ee7d358cb45f8af7f562a33d6.

This revert is to fix the wembley build.

Test: Local wembley build
Change-Id: I651f20ffc6ba11cced5a2a737fd3d77211127221

• services/core/java/com/android/server/rollback/Rollback.java[diff]
• services/core/java/com/android/server/rollback/RollbackPackageHealthObserver.java[diff]
• tests/RollbackTest/Android.bp[diff]
• tests/RollbackTest/RollbackTest/src/com/android/tests/rollback/StagedRollbackTest.java[diff]
• tests/RollbackTest/StagedRollbackTest/src/com/android/tests/rollback/host/StagedRollbackTest.java[diff]