chart.update could lead to fontFamily or fontSize reset to defaults

[trimeyko]

Expected behaviour

After calling chart.update correct values should be applied.

Actual behaviour

Currently if user calls chart.update with styles which is equal to current cleanRecursively call removes these values in chart.update and we lost these values, as a consequence fontFamily or fontSize could reset to defaults because they are hardcoded in getStyle method:

fontFamily: '"Lucida Grande", "Lucida Sans Unicode", Arial, Helvetica, sans-serif'
fontSize: '12px'

ts/Core/Chart/Chart.ts - update()
ts/Core/Renderer/SVG/SVGRenderer.ts - getStyle()

Live demo with steps to reproduce

https://jsfiddle.net/g3p4ve6b/1/

Product version

Highcharts JS v9.1.2

Affected browser(s)

All