No index pattern routing (#4401)

Should redirect to stack management page if there is no index pattern detected.

Signed-off-by: abbyhu2000 <abigailhu2000@gmail.com>

src/plugins/dashboard/public/plugin.tsx

@@ -374,6 +374,13 @@ export class DashboardPlugin
  mount: async (params: AppMountParameters) => {
  const [coreStart, pluginsStart, dashboardStart] = await core.getStartServices();
  this.currentHistory = params.history;
+
+ // make sure the index pattern list is up to date
+ pluginsStart.data.indexPatterns.clearCache();
+ // make sure a default index pattern exists
+ // if not, the page will be redirected to management and dashboard won't be rendered
+ await pluginsStart.data.indexPatterns.ensureDefaultIndexPattern();
+
  appMounted();
  const {
  embeddable: embeddableStart,