Add a new sysprops for toggling game default frame rate

Create a new system property for game default frame
rate. A toggle system setting UI will set
`persist.graphics.game_default_frame_rate.enabled`
via GameMangerService in system_server.

`persist.graphics.game_default_frame_rate.enabled` == 1:
    default frame rate enabled
`persist.graphics.game_default_frame_rate.enabled` == 0:
    default frame rate disabled

Bug: 286084594
Test: m, flash and boots properly on Raven
Change-Id: Iae7ebf39aad6c81475ef3d289d750a818fd4ef79
diff --git a/private/property_contexts b/private/property_contexts
index d884f55..6c81c03 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -1593,3 +1593,6 @@
 
 # Properties for sensor service
 sensors.aosp_low_power_sensor_fusion.maximum_rate u:object_r:sensors_config_prop:s0 exact uint
+
+# Propertues for game manager service
+persist.graphics.game_default_frame_rate.enabled  u:object_r:game_manager_config_prop:s0 exact bool