Revert "priv_app: use per-app selinux contexts"

There's some fragility in how selinux contexts are assigned
to apps with sharedUserId. As a result, some apps which share
a UID can end up in separate selinux domains. This causes bugs
when part of the app has the levelFrom=all categories set, and
other parts only have levelFrom=user resulting in an mls category
mismatch. Until this is fixed, revert back to using levelFrom=user
for priv_app.

This reverts commit 4e7769e0408518f8119b18e08a1369316d98e1c7.
Bug: 188141923
Test: com.google.android.gts.devicepolicy.DeviceOwnerTest#testPendingSystemUpdate

Change-Id: Ic4256f9056f2c218ca94628d0707eb893f83fa5a
diff --git a/private/seapp_contexts b/private/seapp_contexts
index b8e42ea..1d38fd9 100644
--- a/private/seapp_contexts
+++ b/private/seapp_contexts
@@ -158,7 +158,6 @@
 user=_app seinfo=media domain=mediaprovider type=app_data_file levelFrom=user
 user=_app seinfo=platform domain=platform_app type=app_data_file levelFrom=user
 user=_app isEphemeralApp=true domain=ephemeral_app type=app_data_file levelFrom=all
-user=_app minTargetSdkVersion=31 isPrivApp=true domain=priv_app type=privapp_data_file levelFrom=all
 user=_app isPrivApp=true domain=priv_app type=privapp_data_file levelFrom=user
 user=_app isPrivApp=true name=com.google.android.permissioncontroller domain=permissioncontroller_app type=privapp_data_file levelFrom=all
 user=_app seinfo=media isPrivApp=true name=com.android.providers.media.module domain=mediaprovider_app type=privapp_data_file levelFrom=all