Add line event handlers to DataCurve

[axelboc]

Fix #1720

[DataCurve] Add props onLineClick, onLineEnter and onLineLeave

The three new line event handlers all receive the index of the line segment that was interacted with, just like the three existing data point event handlers.

I didn't change the Interactive story since the actions add-on already logs the new events by default:

[loichuder]

Nice integration in the existing code

[chanmSC]

Spectacular! Thank you for this feature!