such means "[any] one like this", so it is indefinite ("[any] one"), not definite ("the one").
Your choices are:
The method does not need the extra parameter. (this particular parameter)
The method does not need an extra parameter. (any extra parameter, including this one)
The method does not need such an extra parameter. (any extra parameter like this one, but possibly a different type of extra parameter)
Using such makes the sentence more specific, e.g. it could be a text parameter or a numeric parameter which is not needed, but an extra boolean parameter might be acceptable. Often, you don't need to be so specific and can leave such out of the sentence (e.g. the second sentence above), in this case meaning that you don't want any extra parameters, regardless of what kind they are.