Update sepolicy with new native boot flag for activity_manager

Whitelist the persistent system properties that will be used as
flags in activity manager experiments.

Bug: 120794810
Test: m, flash, test getting flag value in ActivityManagerService.java
Change-Id: I90a10bc87d6db3a64347b62fd02e6f0b12ac9fa8
diff --git a/private/system_server.te b/private/system_server.te
index 2dcab1e..8aa7785 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -584,6 +584,7 @@
 # server configurable flags properties
 set_prop(system_server, device_config_input_native_boot_prop)
 set_prop(system_server, device_config_netd_native_prop)
+set_prop(system_server, device_config_activity_manager_native_boot_prop)
 
 # BootReceiver to read ro.boot.bootreason
 get_prop(system_server, bootloader_boot_reason_prop)
@@ -940,6 +941,7 @@
   -system_server
   -flags_health_check
 } {
+  device_config_activity_manager_native_boot_prop
   device_config_input_native_boot_prop
   device_config_netd_native_prop
 }:property_service set;