Undefined method `assignee_id?' for ExternalIssue
https://sentry.gitlap.com/gitlab/gitlabcom/issues/13066/
NoMethodError: undefined method `assignee_id?' for #<ExternalIssue:0x007f9bf8d5f638>
app/services/merge_requests/assign_issues_service.rb:7:in `block in assignable_issues'
!issue.assignee_id? && can?(current_user, :admin_issue, issue)
app/services/merge_requests/assign_issues_service.rb:6:in `select'
closes_issues.select do |issue|
app/services/merge_requests/assign_issues_service.rb:6:in `assignable_issues'
closes_issues.select do |issue|
lib/gitlab/metrics/instrumentation.rb:155:in `block in assignable_issues'
trans.method_call_for(#{label.to_sym.inspect}).measure { super }
lib/gitlab/metrics/method_call.rb:23:in `measure'
retval = yield
...
(171 additional frame(s) were not displayed)
ActionView::Template::Error: undefined method `assignee_id?' for #<ExternalIssue:0x007f9bf8d5f638>