Returns the assigned time of the control point at the specified index. The assigned time is the time passed to the
<animationpath>.addControlPoint command when adding the control point.
The assigned time can differ from the actual elapsed time at the control point. This can occur if the first control point time is not 0, or if the constant speed setting is enabled. The
<animationpath>.getTimeAtControlPoint command can be used to get the actual elapsed time at the control point.