[automerge] Fix ViewPager2IdlingResource to unregister IdlingResource 2p: fe2d0843ca

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/providers/MediaProvider/+/17182364

Bug: 218806007
Change-Id: I9180a6a65896447c4da90348ae84c748ca0d665c