Nulls point default behavior and tooltip triggering

[jacques-lebourgeois]

Prerequisites

• I have searched for duplicate or closed feature requests
• I have read the contributing guidelines

Proposal

When drawing a line, a null value in data series breaks the line by default.

1. It may be a preferred behavior to connect sides points in case of null values

2. If a line connects to points ober a null value, it mays the tooltip, it may be disturbing that the mouse above the line triggers the tooltip based on the X axis and displays the value of the other curve.

Motivation and context

Please find use case here

https://stackblitz.com/edit/c7uwr4wx?file=index.js