Insert `finding_uuid` value into `vulnerability_feedback` when creating records

What does this MR do?

This MR inserts a finding_uuid into the Vulnerability::Feedback when feedback is created, if a finding is persisted in the database. This resolves #277133 (closed).

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Availability and Testing

• [-] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done