fix bug in file DependencyTreeUtils.py

[IzaiahSun]

It seems that there is something wrong in function get_direct_objects in file DockerImage/code/NlpUtils/DependencyTreeUtils.py.
On line 71, function getConjunctions is called with two parameters, while on line 14, there is only one parameter for function getConjunctions. I guess that you want to call getConjunctionNPInternal, but it is inside the function, it cannot be called directly. So I change the code to extend conjs defined on line 69 by calling extend method with value return from function getConjunctions.