Merge "Prevent swipe-to-dismiss conversation header" into rvc-dev am: e91a027e am: 891fba38 am: e0de71fb

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11820083

Change-Id: I447daffabaaccbcc544945d25fbf5687d38b30ac