.Net: Anthropic chat generation (non-streaming) and removed FC (#7101)

Part of: #5690 

Anthropic chat generation (non-streaming)

@RogerBarreto 

### Contribution Checklist

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- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄

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Co-authored-by: Roger Barreto <[email protected]>