This harmonizes the appearance of collision shapes and paths between
the editor and running project, in both 2D and 3D.
This means that in 3D, paths are now green and shapes are now cyan
instead of light blue.
This also changes the code used to hide the custom center of mass
property for consistency with other places in the editor
(only this approach worked for Contact Monitor as well).
The Center of Mass property hint in RigidBody2D was also modified
for better usability.
