CSV Export: Adapt for multiple column_names in FUNCTION_INFO

[w31t1]

Some extensions like IO (Fan-In/Fan-Out) generate more than one data column. All these columns shall appear in the CSV output.

[w31t1]

Tests executed on Python 3.12.5 successfully.

I considered an additional security check in L27 (if hasattr(...)):

            if hasattr(extension, 'FUNCTION_INFO') and isinstance(extension.FUNCTION_INFO, dict):

but removed it as the data structure is defined in class OutputScheme.

[w31t1]

Unfortunately I cannot identify the build failures raised by the continuous integration pipeline. Can somebody point me to the problem?