Clear errors list if user decides to continue

Implemented by delegating ServiceManager.errors to ServiceManagerService
This can be broken on a system with enabled translations I'm afraid. We already test for translation in other test cases. See. e.g., https://github.com/yast/yast-services-manager/blob/e83200f078bb3f0fac3c55fbc9f5ee803b763f4f/test/services_manager_target_test.rb#L99