OPT: register_multimodal: minor fix with flag check
OPT: register_multimodal: minor fix with flag check

Former-commit-id: 8b2c46ed9e3b60db4f30e7e6fb386dad793d8a98 [formerly 8a01b51ab7e4bdc92d7bae6003bb6b7460c762b7]
Former-commit-id: a9353f42bc1d2075801f446fc28a408d780b1eed
Former-commit-id: 087ec48d12df221cc1869ab39f85bdbd1cc14e1e
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox