@grafana/e2e: improvements (#25708)

* Set time range when opening a dashboard

* Set UTC timezone when creating a dashboard

* Added flow for selecting options in custom select fields

* Fix flaky test

e2e/shared/smokeTestScenario.ts

@@ -7,9 +7,7 @@ export const smokeTestScenario = {
   addScenarioDashBoard: true,
   skipScenario: false,
   scenario: () => {
-    e2e.getScenarioContext().then(({ lastAddedDashboardUid }: any) => {
-      e2e.flows.openDashboard(lastAddedDashboardUid);
-    });
+    e2e.flows.openDashboard();
     e2e.pages.Dashboard.Toolbar.toolbarItems('Add panel').click();
     e2e.pages.AddDashboard.addNewPanel().click();