Improve dashboard loading error handling#66372

kertal merged 4 commits intoelastic:masterelastic/kibana:masterfrom

kertal:kertal-pr-2020-05-13-dashboard-show-error-message-when-invalid-saved-object-was-loadedkertal/kibana:kertal-pr-2020-05-13-dashboard-show-error-message-when-invalid-saved-object-was-loadedCopy head branch name to clipboard