Bump TCGC to [0.71.2](https://github.com/Azure/typespec-azure/blob/main/packages/typespec-client-generator-core/CHANGELOG.md#0712) and it's related dependencies for the http-client-csharp package. Rerun Generate.ps1 and ensure all existing tests pass. > Generated by [Agentic TCGC Bump for http-client-csharp](https://github.com/microsoft/typespec/actions/runs/32443629278) <!-- gh-aw-agentic-workflow: Agentic TCGC Bump for http-client-csharp, engine: copilot, version: 1.0.63, model: claude-sonnet-4.6, id: 32443629278, workflow_id: bump-tcgc-csharp, run: https://github.com/microsoft/typespec/actions/runs/32443629278 --> <!-- gh-aw-workflow-id: bump-tcgc-csharp --> <!-- gh-aw-workflow-call-id: microsoft/typespec/bump-tcgc-csharp -->
Bump TCGC to 0.71.2 and it's related dependencies for the http-client-csharp package. Rerun Generate.ps1 and ensure all existing tests pass.