dynamic_sensor: Add sensor manager init to sub-HAL 2.1.

Bug: 195964858
Test: Verified dynamic sensor manager is present in sensor list.
Test: Test: See details in testing done comment in
 https://googleplex-android-review.git.corp.google.com/15831086 .
Change-Id: Ia34596d79f8a6c6985b35dcae75126e456f6009e
2 files changed