fix create ROI worfklow in octave

[Remi-Gau]

See

bidspm/tests/tests_slow/tests_cli/test_bidspm_create_roi.m

Line 17 in 4659cd6

moxunit_throw_test_skipped_exception('Need bug fix in CPP ROI extractRoiFromAtlas.');

if: undefined value used in conditional expression
 Error  occurred:
        - Error in validate_arg
                line 533 in /usr/share/octave/6.4.0/m/miscellaneous/inputParser.m
        - Error in parse
                line 404 in /usr/share/octave/6.4.0/m/miscellaneous/inputParser.m
        - Error in extractRoiFromAtlas
                line 46 in /home/remi/github/cpp-lln-lab/bidspm/lib/CPP_ROI/src/atlas/extractRoiFromAtlas.m
        - Error in bidsCreateROI
                line 47 in /home/remi/github/cpp-lln-lab/bidspm/src/workflows/roi/bidsCreateROI.m
        - Error in cliCreateRoi
                line 31 in /home/remi/github/cpp-lln-lab/bidspm/src/cli/cliCreateRoi.m
        - Error in bidspm>executeAction
                line 74 in /home/remi/github/cpp-lln-lab/bidspm/bidspm.m
        - Error in bidspm
                line 26 in /home/remi/github/cpp-lln-lab/bidspm/bidspm.m

[Remi-Gau]

also when used with the python CLI, it just dumps its output in the current directory no matter what output was given.