Merge "Do not register OnBackInvokedCallback for SoftInputWindow." into udc-dev am: a2e448b2

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24677183



Change-Id: I5f0b6ebcb19cfca3e4f518ec4706957890c474ab
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>