Consider deprecate pie chart support in Insights in favor of bar chart
Per @ameliabauerly's comment in https://gitlab.com/gitlab-org/gitlab-ee/issues/11954#note_190935903:
We recommend avoiding pie charts if at all possible, as they are the hardest for us to parse (we're least good at judging volume). In looking at the example pie charts on the existing dashboards, I'm thinking that they could be replaced with column charts, which means we could use the existing GitLab UI component. If for some reason a pie chart is necessary, though, we would have to explore some additional options (perhaps a donut chart or similar?) as we don't currently support pie charts in GitLab UI. Let us know your thoughts on this piece and perhaps we can create a follow-up issue to explore alternatives?
I think we should deprecate pie chart support in Insights ASAP then, as I agree it's hard to parse and can be replaced with a column/bar chart.