You can find the children of Legend object. You can search for the ones that have their Type set to text and relocate them. Below is a sample code to show how to do that. It moves them to left by 0.5 units relative to the legend box. Here 'legend' is your Legend object.
ch = get(legend, 'Children');
textCh = ch(strcmp(get(ch, 'Type'), 'text'));
for i = 1:numel(textCh)
set(textCh(i), 'Position', get(textCh(i), 'Position') + [-0.5 0 0])
end
