Don't crash if default supervision profile owner is not set am: b5fa0a6c5e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16460072

Change-Id: I553dd02243dbebc7267bff208a644ae41151dc92

services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java

@@ -9396,6 +9396,9 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager {
             final ComponentName doComponent = mOwners.getDeviceOwnerComponent();
             final ComponentName poComponent =
                     mOwners.getProfileOwnerComponent(userHandle.getIdentifier());
+            if (supervisorComponent == null) {
+                return null;
+            }
             if (supervisorComponent.equals(doComponent) || supervisorComponent.equals(
                     poComponent)) {
                 return supervisorComponent;