Don't render actuator_assembly_parts_manual.png twice

Having the same file rendered twice will create problems when changing to Ninja for the rendering system. There can be only one (rule to create each artifact)!

Also simplify the code by reusing the logic from the other images that needs special upright variants.

Use distance=390 for all 3 images - now also for the inverted microscope. The inverted has the fewest parts so does not need the distance extended to 400.