Add adaptive haptics restricted system property

Create adaptive haptics system property to store adaptive haptics enable
state.

Bug: 198239103
Test: Verified system property usage
Change-Id: I5d4f0a5c8ec4a5b0ce18bc03a6d30879dd76d58b
Signed-off-by: Chris Paulo <chrispaulo@google.com>
diff --git a/private/property_contexts b/private/property_contexts
index 1442fa9..b8503bd 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -1466,3 +1466,6 @@
 # properties for tuner
 ro.tuner.lazyhal    u:object_r:tuner_config_prop:s0 exact bool
 tuner.server.enable u:object_r:tuner_server_ctl_prop:s0 exact bool
+
+# Adaptive haptics settings property
+vibrator.adaptive_haptics.enabled u:object_r:adaptive_haptics_prop:s0 exact string