Performance improvement - update at most at the "Update rate"

Created by: wxmerkt

This PR achieves two things:

1. It only renders when triggered by the RViz update callback: This way, we respect the "Update rate" setting set in the Global Options in RViz. Currently it renders on every incoming message - which for the Anymal controller is 400 Hz - and at ~1.5-2ms per update (due to the pointer resetting and PinocchioLinkUpdater callbacks), this quickly blocks the GPU and results in dropping RViz fps.
2. It catches a few invalid user inputs in the URDF and arrow settings which previously led to RViz crashing