Do not allow to revert setForceSafeLabel

Test: Built
Bug: 116798569
Change-Id: I3f26d4466c84d3decb1c4962fb45e900ba35f68e
diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index b8241d0..52b849f 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -359,7 +359,7 @@
             // The system server should never make non-oneway calls
             Binder.setWarnOnBlocking(true);
             // The system server should always load safe labels
-            PackageItemInfo.setForceSafeLabels(true);
+            PackageItemInfo.forceSafeLabels();
 
             // Default to FULL within the system server.
             SQLiteGlobal.sDefaultSyncMode = SQLiteGlobal.SYNC_MODE_FULL;