Address reviews

Co-authored-by: Diego Ferigo <[email protected]>

src/jaxsim/api/ode.py

@@ -156,7 +156,7 @@ def system_velocity_dynamics(
                 == jnp.arange(model.number_of_links())
             ).any(axis=-1, keepdims=True),
             W_f_Ci,
-            0.0,
+            jnp.zeros_like(W_f_Ci),
         ).sum(axis=0)
 
     # ====================