fix typo

Author: sdgilley

articles/ai-foundry/includes/install-csharp-packages.md

@@ -16,7 +16,7 @@ To work with Azure AI services in your .NET project, you'll need to install seve
 # Add Azure AI SDK packages
 dotnet add package Azure.Identity
 dotnet add package Azure.AI.Projects
-dotnet add package Azure.AI.Agents.Persistant
+dotnet add package Azure.AI.Agents.Persistent
 dotnet add package Azure.AI.OpenAI
 dotnet add package Azure.Search.Documents
 ```