Use of deprecated Microsoft.Extensions.AI.Ollama package in official samples

[fahadmohammad]

I noticed that some official samples/reference code are still using the Microsoft.Extensions.AI.Ollama package.
However, this package is now marked as deprecated, and the recommendation is to use OllamaSharp instead.
This creates confusion for developers trying to follow the official guidance, especially when:

• The sample code relies on types like OllamaChatClient
• These types are no longer available or maintained
• The recommended alternative (OllamaSharp) has a different API surface and does not support the same extension methods (e.g., AsBuilder(), UseFunctionInvocation())

[github-actions]

👋 Thanks for contributing @fahadmohammad! We will review the issue and get back to you soon.