Extra bottom margin when using sparkline

[dragonofmercy]

Description

When a chart is built with sparkline option, an extra margin (about 2px) is visible at the bottom.

Steps to Reproduce

Just create a sparkline chart and put it inside a div with a border

Expected Behavior

Remove extra margin

Actual Behavior

See screenshot below

Screenshots

Reproduction Link

https://codepen.io/dragonofmercy/pen/raeqYNm