[MR Widget V2] Use information-o instead of question-o for help popovers

Summary

The current implementation of the help popover uses a question-o icon. The design specs, on the other hand, use an information-o icon.

Implementation plan

• Extend the help popover component to allow using information-o whenever required.
• Update https://gitlab.com/gitlab-org/gitlab/-/blob/master/app/assets/javascripts/vue_merge_request_widget/components/widget/widget.vue to instruct the help popover to use the information-o
• Update https://gitlab.com/gitlab-org/gitlab/-/blob/master/app/assets/javascripts/vue_merge_request_widget/components/widget/widget_content_row.vue to instruct the help popover to use the information-o

Testing

• Make sure review-qa-non-blocking job which is run as part of review-app child pipeline is green. (It selectively runs devopsgovern specs)

Verification steps

1. Go to https://gitlab.com/svedova/security-reports/-/merge_requests/1
2. Check that the Security Reports help popovers have the information-o icon