Enhance logging in all github import workers on raised exceptions
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The following discussion from !70012 should be addressed:
- [ ] @dstull started a [discussion](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/70012#note_684382418): (+4 comments)
> I'm not sure about this and other uses of `fail_import` that I've added ...
>
> What is the usual rule here on setting this to `true` or `false`?
#### Technical Note:
The labkit-ruby upgrade (part of upgrading to Ruby 3.0) injects info into logs - to track which deployment stage we execute on (main, cny)- _after_ the event leaves gitlab-rails. Since it writes the `stage` log field, it overwrites any `stage:` value, so don't use this value in the logs. See !111590
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