fix(config-loader): do not set arguments if nil

[portellaa]

When setting the arguments for the task using an optional value, in this case nil, it was raising a bad access exception from the Task.

To avoid this i added a validation to the arguments settings those only when there is a non nil value.

[iabudiab]

Yes, good catch. I'll merge and take care of the Linux build later 😉 Thanks!