Tool error handling

[jgauffin]

Add integration point to be able to handle tool errors.

For instance the ability to:

• Generate a custom reply if the user does not specify all tool arguments
• Generate a custom reply if the tool could not generate the desired result.

[awaescher]

When and where? For example, if you're using the Chat class, the possibilities are different than when using OllamaSharp with Semantic Kernel oder Microsoft.Extensions.AI.