Polar chart: Pane's background doesn't match gridLineInterpolation option

[pawelfus]

Expected behaviour

An option to change behaviour of the pane's background, to match the shape of the grid lines. It can be either considered a bug, a or a feature. Probably the same issue could be resolved/discussed for Axis.line

Note: I think a similar issue was reported a few years ago, but I couldn't find it..

Actual behaviour

Circular background

Live demo with steps to reproduce

https://jsfiddle.net/BlackLabel/mac3ub56/1/

Product version

N/A

Affected browser(s)

N/A