Parse Server: File metadata endpoint bypasses `beforeFind` / `afterFind` trigger authorization

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.9 and 9.5.0-alpha.9, the file metadata endpoint (GET /files/:appId/metadata/:filename) does not enforce beforeFind / afterFind file triggers. When these triggers are used as access-control gates, the metadata endpoint bypasses them entirely, allowing unauthorized access to file metadata. This issue has been patched in versions 8.6.9 and 9.5.0-alpha.9.