Adapt to new embedding method for Highcharts

[jeffbl]

Given that there was a change in how HighCharts embed charts on their own website, do we need to update how we recognize charts? The concern is that if they have updated their mechanism, this might expand out to other sites, greatly reducing the number of charts we can actually handle in the extension.

If this is blocking and there is no feasible technical solution, let's contact HighCharts to get their take. If embedded HighCharts content becomes opaque to us, we'd have to look for another format to support, otherwise we will not have any charts support at all in the extension.

@jaydeepsingh25 putting this in Backlog, but pinging you for comment, in case I've misunderstood the issue/implications.

[jeffbl]

Not sure if this is an example of an embedding issue, but not clear why the extension does not put IMAGE buttons on the Highcharts charts at this link:
https://www.worldgovernmentbonds.com/country/canada/

[jeffbl]

@shahdyousefak would be great if we could use the Highcharts site itself (see link in original comment)
@jaydeepsingh25 this is one that if we could detect it, is a single trend line chart I'd expect would work:
https://www.highcharts.com/demo/highcharts/line-log-axis

If we can't access these, do we need to reach out to Highcharts to figure something out?