Add reporting for showing warning toasts

Change-Id: Ie79914190c48df2fd12f92187374506144a80c1e
diff --git a/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager.ts b/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager.ts
index 162caa4..bd3c052 100644
--- a/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager.ts
+++ b/polygerrit-ui/app/elements/core/gr-error-manager/gr-error-manager.ts
@@ -335,6 +335,7 @@
     el.show(text, actionText, actionCallback);
     this._alertElement = el;
     this.fire('iron-announce', {text}, {bubbles: true});
+    this.reporting.reportInteraction('show-alert', {text});
   }
 
   _hideAlert() {