Add keystore_key:attest_unique_id to priv_app.

Only privileged apps are supposed to be able to get unique IDs from
attestation.

Test: CTS test verifies the negative condition, manual the positive
Bug: 34671471
Change-Id: I9ab3f71b1e11ed1d7866ff933feece73152d2578
diff --git a/private/priv_app.te b/private/priv_app.te
index 38ce673..a703ba8 100644
--- a/private/priv_app.te
+++ b/private/priv_app.te
@@ -114,6 +114,9 @@
 # TODO: narrow this to just MediaProvider
 allow priv_app mnt_media_rw_file:dir search;
 
+# Allow privileged apps (e.g. GMS core) to generate unique hardware IDs
+allow priv_app keystore:keystore_key gen_unique_id;
+
 read_runtime_log_tags(priv_app)
 
 ###