Adjust the read operation without using `Vulnerabilities::Feedback` where it is needed

This issue will be used to adjust the read operations after removal of `Vulnerabilities::Feedback so that we do not depend on feedback model anymore when FF is on. We also created other issues when the scope is big.

Implementation plan:

For all the cases listed below, use deprecate_vulnerabilities_feedback FF:

• Adjust https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/app/services/vulnerabilities/create_service.rb#L48-49 (!100234 (merged))
• Adjust and check https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/app/models/vulnerabilities/finding.rb (!105134 (merged))
• Adjust https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/app/finders/security/pipeline_vulnerabilities_finder.rb (!105936 (merged))
• Adjust https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/app/helpers/vulnerabilities_helper.rb (!105134 (merged), !106992 (merged))
• Adjust Security::FindingsFinder (created issue: #377584 (closed), !105097 (merged))
• Adjust Security::VulnerabilitiesFinder (!102238 (merged))
• Adjust MergeRequestController not to use Vulnerabilities::Feedback (created issue: #378353 (closed))
• Adjust VulnerabilityFeedbackController (created issue: #368311 (closed))
• Adjust the use of Vulnerabilities::FindingsPreloader (created issue: #384221 (closed), !106150 (merged))
• Adjust Vulnerabilities::FindingEntity (!106992 (merged), !111438 (merged) )
• Check ee/app/services/security/ingestion/tasks/ingest_vulnerabilities/create.rb whether the use of dismissal feedback need adjustment (!107935 (merged))
• Check the use of Vulnerabilities::DestroyDismissalFeedbackService (!107935 (merged))
• Adjust Security::Ingestion::Tasks::IngestIssueLinks (created issue: #384222 (closed))
• Adjust https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/app/graphql/types/vulnerability_type.rb#L167 to avoid merge_request_feedback in merge_request method (!106630 (merged))
• Check the https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/app/models/security/finding.rb (checked as part of #384235 (closed), !106992 (merged))