Inconsistent feedback responses on `merge_requests/${id}/${type}_reports` and `vulnerability_feedback` endpoints

Summary

API responses of merge_requests/${id}/${type}_reports and vulnerability_feedback?report_type=${report_type} endpoints are returning different feedback records.

This is happening because the vulnerability_feedback endpoint is utilizing the only_valid_feedback scope of Vulnerabilities::Feedback model and the other one is not.

Steps to reproduce

TBD

Example Project

TBD

What is the current bug behavior?

Inconsistent data on 2 different endpoints.

What is the expected correct behavior?

Consistent data.

Relevant logs and/or screenshots

TBD

Output of checks

This bug happens on GitLab.com

Results of GitLab environment info

All environments

Possible fixes

1. TBD
2. Ensure the frontend still works after the backend change

Implementation plan

• frontend set value of dismissal_feedback property to null in revertDismissVulnerability (!45954 (diffs)); we need to do it until we have #207489 (closed) resolved (the reason for that is that we have fallback defined in https://gitlab.com/gitlab-org/gitlab/blob/369d3ae038b81a75376d2a752a30b563e437fe42/ee/app/assets/javascripts/vue_shared/security_reports/components/modal.vue#L109, so even when we set dismissalFeedback to null, it is still incorrectly rendered),
• backend add callbacks to ee/app/models/vulnerabilities/feedback.rb to touch the pipeline after save and after destroy: this will invalidate Redis cache from MergeRequest#compare_reports (https://gitlab.com/gitlab-org/gitlab/blob/ca279741b2d5160b3914dd9d15b127b8ae873447/app/models/merge_request.rb#L1442),
• backend add pipeline to feedback_params in ee/app/services/vulnerabilities/dismiss_service.rb as latest successful pipeline with security reports,
• backend add background migration to update pipeline_id for feedback missing id value