vulnerability finding modal does not have canAdminVulnerability injection in MR widget

Summary

With standalone_finding_modal_merge_request_widget enabled, the finding modal is shown on the MR widget. It seems canAdminVulnerability is not provided in that use case. It was recently added in Hide vulnerability dismiss buttons for users wi... (!138867 - merged) • Daniel Tian • 17.0.

Possible fixes

1. Make sure canAdminVulnerability is provided from backend on the MR widget