Puts mPm.onNewUserCreated inside Binder.withCleanCallingIdentity

PackageManagerService.onNewUserCreated eventually calls
ComputerEngine.getInstalledPackages. And it requires callingUid to have
INTERACT_ACROSS_USERS permission. That was failing some tests for auto.
This CL makes sure that method is called with clean calling identity.

Bug: 228253821
Test: atest CtsMultiUserTestCases:android.multiuser.cts.UserManagerTest#testCreateUser_withNewUserRequest_shouldCreateUserWithCorrectProperties
Change-Id: Ia06b9d5e6501140541e8d520350368df1abe2f15

services/core/java/com/android/server/pm/UserManagerService.java

@@ -4207,7 +4207,9 @@ public class UserManagerService extends IUserManager.Stub {
             writeUserListLP();
         }
         updateUserIds();
-        mPm.onNewUserCreated(preCreatedUser.id, /* convertedFromPreCreated= */ true);
+        Binder.withCleanCallingIdentity(() -> {
+            mPm.onNewUserCreated(preCreatedUser.id, /* convertedFromPreCreated= */ true);
+        });
         dispatchUserAdded(preCreatedUser, token);
         return preCreatedUser;
     }