Fix and deduplicate compute_no_op_goal

[cgokmen]

Recently we had to implement a compute_no_op_action function on controllers in order to be able to make robots stay still. There also is a compute_no_op_goal function which is used to populate the initial goal after a controller reset. But the latter does not always do what you expect (e.g. see multifinger) and might even be redundant since the goal could simply be computed using the no_op action.

[cgokmen]

CC @Arpitrf @ChengshuLi