setByTrigger: make sure that defaults for this can actually be set

[Remi-Gau]

See summary of the problem below

function [cfg] = checkParameters(cfg)
    %

    ...

    cfg = setDefaultFields(cfg, fieldsToSet);

    cfg = setParametersMtMst(cfg);

    cfg = setMRI(cfg);

    ...

end


function cfg = setParametersMtMst(cfg)

    switch lower(cfg.design.localizer)

        case 'mt_mst'

        ...

        case 'mt'

            ...

            % SETS the value if not defined before
            fieldsToSet.timing.IBI = 4;

            ...

    end

    cfg = setDefaultFields(cfg, fieldsToSet);

end

function cfg = setMRI(cfg)

    ...

    cfg = setDefaultFields(cfg, fieldsToSet);

    cfg = setPacedByTrigger(cfg);

end

function cfg = setPacedByTrigger(cfg)

    if cfg.pacedByTriggers.do

        ...
        % CANNOT override the value because it was set before in setParametersMtMst
        fieldsToSet.timing.IBI = 0;

        ...

        cfg = setDefaultFields(cfg, fieldsToSet);

    end

end