Fixed error thrown when the 'pre_populate_source' property is not an array
Fixed error thrown when the 'pre_populate_source' property is not an array

psychoticmeow/journey-cms,embarknow/journey-cms,embarknow/journey-cms,psychoticmeow/journey-cms,symphonycms/symphony-3,symphonycms/symphony-3,embarknow/journey-cms,embarknow/journey-cms,psychoticmeow/journey-cms,psychoticmeow/journey-cms,embarknow/journey-cms,psychoticmeow/journey-cms