Command migrate customers creates CT despite incorrect user group.

Prereq.: Only "old" user CT exists.

Steps:

1. Execute command php bin/console ibexa:migrate:customers --input-user-group=INPUT-USER-GROUP --create-content-type and provide user group that does not exist.
2. Examine result.

Actual result: Error occurs "Could not find 'Content' with identifier" but new CT is created. Please see attached.
Expected result: Error occurs and new CT is not created until correct parameters are provided.