Take into account y_scale and y_offset when calculating blend init.
Take into account y_scale and y_offset when calculating blend init.

The blend spline needs to take into account that the spline it is blending to may be scaled and shifted. As soon as the blend spline is complete, the next CubicInit will be using the y_scale and y_offset, so this only needs to be done for the BlendInit.

PiperOrigin-RevId: 229201677
Change-Id: I6747ab71aea03a22d28528a1e5bae91de6dff11d

google/motive,google/motive