Update error telemetry site to add callstacks as comments to existing issues

Currently, while triaging errors in the error telemetry site, when you come across a callstack which is slightly different from the one for which issue is already logged, all you can do is add link to the issue which marks it as triaged.
The corresponding github issue has no knowledge of such linked errors.

This issue is to enable adding such callstacks as comments to the github issues