Add psap_ai flag to protect DeviceConfig flags

Android 16 adds restrictions to the DeviceConfig flags that can
be modified by the shell user; to support this, the
WRITE_DEVICE_CONFIG permission will be removed from the shell
user's manifest. This commit adds a new flag in the psap_ai
namespace that will be used to flag all changes to support
these restrictions.

Bug: 364083026
Flag: android.security.protect_device_config_flags
Test: Build
Change-Id: I763594e84b31e75e62f36c4aafe5edbefecc296d