Update sms-opt-out-api-csharp.md

Author: dbasantes

articles/communication-services/quickstarts/sms/includes/sms-opt-out-api-csharp.md

@@ -19,7 +19,7 @@ Get started with Azure Communication Services SMS Opt-out API by leveraging the
 - An Azure account with an active subscription. [Create an account for free](https://azure.microsoft.com/free/?WT.mc_id=A261C142F).
 - The .NET Core SDK version must be higher than v6 for your operating system.
 - An active Communication Services resource and connection string. See [Create a Communication Services resource](https://learn.microsoft.com/azure/communication-services/quickstarts/create-communication-resource).
-- An SMS-enabled telephone number. See [Get a phone number](https://learn.microsoft.com/azure/communication-services/quickstarts/telephony/get-phone-number) and `allowlisted` as described in the beginning of the article.
+- An SMS-enabled telephone number. See [Get a phone number](https://learn.microsoft.com/azure/communication-services/quickstarts/telephony/get-phone-number).
 
 ## Sample code to use Opt-Out API