Add addition error data of cause

[florianmutter]

Package + Version

• [x] @sentry/browser
• [ ] @sentry/node
• [ ] raven-js
• [ ] raven-node (raven for node)
• [ ] other:

Version:

4.6.6

But also effects 5.0.0

Description

The cause of an error can be attached to an error and Sentry will display the causes stacktrace. It will not extract the additional data of the cause. This can be very useful information. It should extract the additional data of the cause as well (probably only to a certain depth).

I think this must happen somewhere around here: https://github.com/getsentry/sentry-javascript/blob/master/packages/integrations/src/extraerrordata.ts#L88

[HazAT]

We happily accept a PR for this :)