Restore resetKeyStore() logic of clearing SYSTEM uid

Keystore no longer clears keys critical to device encryption flow
so no need to skip clearing SYSTEM's keystore entries here.

Bug: 34600579
Test: Add device lock under synthtic password, goto Settings/security/encryption,
      tap clear credentials and verify device lock is still intact.
Change-Id: I191a545181771693fd2d75f1c23d14a6b74278af

services/core/java/com/android/server/locksettings/LockSettingsService.java

@@ -162,7 +162,7 @@ public class LockSettingsService extends ILockSettings.Stub {
      */
     private static final int[] SYSTEM_CREDENTIAL_UIDS = {
             Process.WIFI_UID, Process.VPN_UID,
-            Process.ROOT_UID };
+            Process.ROOT_UID, Process.SYSTEM_UID };
 
     // This class manages life cycle events for encrypted users on File Based Encryption (FBE)
     // devices. The most basic of these is to show/hide notifications about missing features until