allow com.android.vending to access vendor_apex_file

Widevine is now in an APEX. com.android.vending tries to access widevine
apex, which results in a sepolicy error. Modifying sepolicy to allow
com.android.vending to access apex directory.

Bug: 247100406
Test: https://android-build.googleplex.com/builds/abtd/run/L54600000956675013
Change-Id: Ie73411dbe1c35027cb498c2cfa6847515a41d08a
diff --git a/private/priv_app.te b/private/priv_app.te
index 4dcd1fb..8c965fc 100644
--- a/private/priv_app.te
+++ b/private/priv_app.te
@@ -190,6 +190,11 @@
 # Required for Phonesky to be able to read staged files under /data/app-staging.
 allow priv_app staging_data_file:dir r_dir_perms;
 
+# Allow com.android.vending to access files under vendor/apex as well as system apex files.
+# This is required for com.android.vending to handle APEXes for e.g. delta patch optimization.
+allow priv_app vendor_apex_file:dir r_dir_perms;
+allow priv_app vendor_apex_file:file r_file_perms;
+
 # allow priv app to access the system app data files for ContentProvider case.
 allow priv_app system_app_data_file:file { read getattr };