making AI search property optional while creating capability host agent

[jayesh-tanna]

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sdk/ml/azure-ai-ml/azure/ai/ml/operations/_capability_hosts_operations.py:251

• Since vector store connections are now optional, consider updating the error message or accompanying documentation to explicitly state that only the OpenAI service connection is required for a Project workspace kind.

OpenAI service connection is empty for a Project workspace kind.

[azure-sdk]

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azure-ai-ml