Fix utility download chart
Created by: cschloer
The className for the chart was being used to access the DOM in order to download as a png. That className was using the account_number. For generic utility bills the account_number is null so no className is added.
Updated the chart to use the account_id instead of the account_number.
To test this simply upload a bill to a generic account (Electric Bill, Oil Bill, etc.) and try to download the chart.