Pass metric identifier for training link clicked on vulnerability details page

This issue is a follow-up of this > #348589 (closed), please read it first.

These metrics were captured in this MR > !80643 (merged)

• The URL of the training link
• The GitLab page/context from which it was clicked (e.g. MR, pipeline, vulnerability details page)

In this issue, let's capture this:

• Not required but very nice to have: Identifier(s) of the finding/vulnerability