Remove vuln_report_new_project_filter feature flag

Now that the new project filter on the vulnerability report has been enabled by default, we should remove the vuln_report_new_project_filter feature flag and remove the old, deprecated project filter. We should also remove any code that fetches project data before the vulnerability report renders, which was used for the deprecated project filter but is no longer needed for the new one.

Implementation plan

• Delete ee/app/assets/javascripts/security_dashboard/components/shared/filters/project_filter_deprecated.vue
• Delete config/feature_flags/development/vuln_report_new_project_filter.yml
• Remove shouldShowNewProjectFilter() in ee/app/assets/javascripts/security_dashboard/components/shared/filters/filters_layout.vue and the place in the template that uses it
• Remove the push_frontend_feature_flag(:vuln_report_new_project_filter) line from ee/app/controllers/groups/security/vulnerabilities_controller.rb and ee/app/controllers/security/vulnerabilities_controller.rb
• Remove the projects Apollo query from ee/app/assets/javascripts/security_dashboard/components/shared/vulnerability_report.vue and the place in the template that uses it
• Remove the projects prop from ee/app/assets/javascripts/security_dashboard/components/shared/filters/filters_layout.vue and every place that uses it in the file
• Fix any broken tests