Remediations are incorrectly set for all the vulnerabilities

Why are we doing this work

The vulnerability remediations of a report artifact are being assigned to all vulnerabilities reported by that artifact by mistake without obeying the "id" or "cve" attributes. Git history points the MR !65959 (merged).

Relevant links

• This regression has been introduced by !65959 (merged).

Implementation plan

• backend Fix the logic in ee/lib/ee/gitlab/ci/parsers/security/common.rb to match remediations with the correct vulnerabilities.
• database Run a migration to fix the existing data