Add ViewPager2 to prebuilts

./prebuilts/sdk/update_prebuilts.py 6226016 --stx

Test: make ANDROID_BUILDSPEC=vendor/google/build/app_build_spec.mk -j32
Fixes: 150782390

Change-Id: Ia8360aea63069f10f5a985f6fcddc9b084cd6f87
18 files changed