.Net: Update gen_ai traces and logs

[markwallace-microsoft]

Motivation and Context

The gen_ai semantic convention has gone through some updates since we started generating telemetry for gen_ai operations. We would like to align with the latest conventions, and most importantly allow our users to visualize the gen_ai traces on the Azure AI Foundry Tracing UI, which relies on the gen_ai conventions.

Description

1. Updates the gen_ai telemetry module to align with the latest gen_ai convention so that all AI connectors generate telemetry data that can be visualized on Azure AI Foundry.
2. Update samples and documentation.
   • Create a zone for .Net here: https://review.learn.microsoft.com/en-us/semantic-kernel/concepts/enterprise-readiness/observability/telemetry-with-azure-ai-foundry-tracing?branch=main
3. Unit tests for the update.

Note that this is a breaking change as this feature is still experimental. Anyone who is relying on the previous gen_ai conventions should also update.

Python implementation: #10173