fix(alerting): fix breadcrumb for Alert Activity page

- Use conditional navId based on feature flag (alert-activity for V2, alert-alerts for legacy)
- Remove pageNav.text to avoid extra breadcrumb level
- Use renderTitle instead to set page title without affecting breadcrumb
- Fixes breadcrumb showing 'Page not found > Alerts' to 'Alerting > Alert Activity'

public/app/features/alerting/unified/triage/Triage.tsx

@@ -3,20 +3,22 @@ import { UrlSyncContextProvider } from '@grafana/scenes';
 import { withErrorBoundary } from '@grafana/ui';
 
 import { AlertingPageWrapper } from '../components/AlertingPageWrapper';
+import { shouldUseAlertingNavigationV2 } from '../featureToggles';
 
 import { TriageScene, triageScene } from './scene/TriageScene';
 
 export const TriagePage = () => {
+  const useV2Nav = shouldUseAlertingNavigationV2();
+  const navId = useV2Nav ? 'alert-activity' : 'alert-alerts';
+
   return (
     <AlertingPageWrapper
-      navId="alert-alerts"
+      navId={navId}
       subTitle={t(
         'alerting.pages.triage.subtitle',
         'See what is currently alerting and explore historical data to investigate current or past issues.'
       )}
-      pageNav={{
-        text: t('alerting.pages.triage.title', 'Alerts'),
-      }}
+      renderTitle={() => t('alerting.pages.triage.title', 'Alert Activity')}
     >
       <UrlSyncContextProvider scene={triageScene} updateUrlOnInit={true} createBrowserHistorySteps={true}>
         <TriageScene key={triageScene.state.key} />