private method `file' called for #<CarrierWave::Storage::Fog::File:0x00007faf00ae0ef0>

https://sentry.gitlab.net/gitlab/staginggitlabcom/issues/2696867

NoMethodError: private method `file' called for #<CarrierWave::Storage::Fog::File:0x00007faf00ae0ef0>
  from lib/api/group_avatar.rb:21:in `block (2 levels) in <class:GroupAvatar>'