Clean up AI quickstarts

[gewarren]

Fixes #45937:

• Remove "clone sample repo" and azd instructions
• Use snippet tags instead of line ranges to prevent missing code in published docs

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Internal previews

📄 File	🔗 Preview link
docs/ai/quickstarts/build-chat-app.md	CustomerIntent: As a .NET developer new to AI, I want deploy and use sample code to interact to learn from the sample code.
docs/ai/quickstarts/build-vector-search-app.md	Build a .NET AI vector search app
docs/ai/quickstarts/chat-local-model.md	Quickstart - Connect to and chat with a local AI using .NET
docs/ai/quickstarts/create-assistant.md	Create a minimal AI assistant using .NET
docs/ai/quickstarts/evaluate-ai-response.md	docs/ai/quickstarts/evaluate-ai-response
docs/ai/quickstarts/generate-images.md	CustomerIntent: As a .NET developer new to OpenAI, I want deploy and use sample code to interact to learn from the sample code to generate images.
docs/ai/quickstarts/prompt-model.md	Quickstart - Connect to and prompt an AI model with .NET
docs/ai/quickstarts/structured-output.md	Request a response with structured output
docs/ai/quickstarts/use-function-calling.md	CustomerIntent: As a .NET developer new to OpenAI, I want deploy and use sample code to interact to learn from the sample code how to extend the model using Tools.