Handle events overview when event definition is missing (7.0)#25735

ryan-carroll-graylog merged 1 commit into7.0Graylog2/graylog2-server:7.0from

backport-7.0/13756-when-an-event-definition-has-been-removed-the-events-overview-widget-will-error-when-trying-to-reference-itGraylog2/graylog2-server:backport-7.0/13756-when-an-event-definition-has-been-removed-the-events-overview-widget-will-error-when-trying-to-reference-itCopy head branch name to clipboard