Update index.yaml (cloudflare#22543)

* Update index.yaml

Corrected the availability of the Advanced HTTP DDoS Alerts. They are only available for Enterprise customers with the Advanced DDoS add-on.

* Apply suggestions from code review

---------

Co-authored-by: Patricia Santa Ana <[email protected]>

Author: 2 people

src/content/notifications/index.yaml

@@ -139,7 +139,7 @@ entries:
 
   - name: Advanced HTTP DDoS Attack Alert
     audience: "[WAF](/waf/) or [CDN](/cache/) customers with the [Advanced DDoS Protection](/ddos-protection/) subscription who want to receive a notification when Cloudflare has mitigated attacks that generate more than the configured number of requests per second (100 rps by default)."
-    availability: Enterprise plans.
+    availability: Enterprise plans with the Advanced DDoS Protection add-on.
     associatedProducts: DDoS Protection
     nextSteps: No action needed. Refer to [DDoS alerts](/ddos-protection/reference/alerts/) for more information.
     otherFilters: |-