Allow dot sizing based on data as it is currently done in kibana. Ideally this is through a `dotAccessor` to pull from data rather than using the `pointStyleAccessor` function prop.  Related to https://github.com/elastic/elastic-charts/issues/66 **Checklist** - [x] this request is checked against already exist requests - [x] every related Kibana issue is listed under `Kibana Cross Issues` list - [x] `kibana cross issue` tag is associated to the issue if any kibana cross issue is present
Allow dot sizing based on data as it is currently done in kibana.
Ideally this is through a
dotAccessorto pull from data rather than using thepointStyleAccessorfunction prop.Related to #66
Checklist
Kibana Cross Issueslistkibana cross issuetag is associated to the issue if any kibana cross issue is present