Throw exception if ParameterConverters cannot convert to the desired type.
Description
Currently if ParameterConverters can't convert to the desired type, it just returns the parameter as a string. This then falls over in some unrelated code later in the process when it can't call the step because of mismatching parameter types. To aid in debugging this, it should throw an Exception detailing the type that it can't convert to, so it can be caught early.
Currently if ParameterConverters can't convert to the desired type, it just returns the parameter as a string. This then falls over in some unrelated code later in the process when it can't call the step because of mismatching parameter types. To aid in debugging this, it should throw an Exception detailing the type that it can't convert to, so it can be caught early.