Handle a case when job configuration can be invalid

ee/lib/ee/gitlab/ci/config/entry/jobs.rb

@@ -20,9 +20,11 @@ module EE
             end
 
             def bridge?(name)
-              config.fetch(name).key?(:trigger) &&
+              config.fetch(name).yield_self do |value|
+                value.is_a?(Hash) && value.key?(:trigger) &&
                   cross_project_triggers_enabled?
               end
+            end
 
             def cross_project_triggers_enabled?
               ::Feature.enabled?(:cross_project_pipeline_triggers, default_enabled: true)