.NET: Azure.AI.Agents Package Split + Initial Extensions (#1657)

* Move packages

* Update nuget.config

* Address Xmldoc

* Remove format from branches checks

* Address Xmldocs

* Add more details to the implementation

* Moving Agent logic to ChatClient

* Adding Name and Id overrides to AzureAIAgent

* Updating extensions

* Add GetAiAgent extensions

* Adding support for version as name can conflict 409 using the Agents API with same name

* Addressing more updates to the extensions

* More improvements

* Remove debugging code from sample

* Address copilot feedback

* Apply suggestions from co-pilot code review

.github/workflows/dotnet-format.yml

@@ -7,7 +7,7 @@ name: dotnet-format
 on:
   workflow_dispatch:
   pull_request:
-    branches: ["main", "feature*"]
+    branches: ["main"]
     paths:
       - dotnet/**
       - '.github/workflows/dotnet-format.yml'