Graph vertical panning

Haven't found any in-built solutions, which is kind of crazy. Only being able to pan horizontally makes no sense to me. Such is the way.

This might help, but means chart may have set dimensions: https://api.highcharts.com/highcharts/chart.scrollablePlotArea. Not sure how it would act with zoom.

Other options are to just roll out our own thing where we figure out the scrolling delta and change the data that gets shown based on that.