dynamic_sensor: Add stubbed sensor multi-HAL 2.1 support. am: 2ac7393bd8 am: c939db938c

Original change: https://googleplex-android-review.googlesource.com/c/platform/hardware/libhardware/+/15806307

Change-Id: I1e7f9e8a1dc30765c4e06e7e76600a24238e5583