use photo mesh generation only on uncovered parts

No, it is not possible to do it automatically (or it can be used using the image list, but in that case you need to create that list and find the images, so basically it is the same as already advised).
In the proposed workflow the images will be used only on the parts, where the laser scans aren’t, so the laser scan point cloud shouldn’t be influenced by images (as on those parts they will be disabled).
In cases like this you can also change the Default grouping factor (How to give more priority to laser scans in reconstrution - #2 by OndrejTrhan) so the laser scan’s point cloud will have the higher priority on the places where also point cloud from images is appearing.