Fix temporary workaround for setting ball's velocity to zero

[Adman]

Will be fixed on Webots side in next release (see the issue cyberbotics/webots#2899)

• remove the workaround from our code + test it.

[mrshu]

@Adman This has been fixed already, right?

[Adman]

@mrshu Webots created some fix but the problem still persists there.