Is your feature request related to a problem? Please describe.
The current implementation of the line chart (see line_geometries.tsx) does not interpolate the paths for the animation. Curved paths are not animated and also this causes an error when showing/hiding a line associated with a series (see #51 (comment))

See pmndrs/react-spring#77

Describe the solution you'd like
Custom interpolation function to handle line animations

Describe alternatives you've considered
It's possible that we don't want to animate the line paths and choose to animate a different property of the line chart.

Additional context

Kibana Cross Issues
n/a

Checklist

• this request is checked against already exist requests
• every related Kibana issue is listed under Kibana Cross Issues list
• kibana cross issue tag is associated to the issue if any kibana cross issue is present