Correct 2 little bugs

[ylenianistico]

1. Remove rotation here: base velocity is given already in the world frame by the leg odometry plugin
2. Compute angular velocity using quat_est and quat_dot at the same time step: as it is now, the code is using quat_est computed at a previous step. Not problematic because of the high frequencies, but it needs to be corrected
3. Adjust the sign here