Add method for registry model create/update with system metadata

[chaoyu-msft]

Description

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• The pull request does not introduce [breaking changes]
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Testing Guidelines

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[Copilot]

Pull Request Overview

This pull request introduces a new method to handle model create/update operations with system metadata when operating in a registry context. Key changes include:

• Adding new imports required for building and converting create/update requests.
• Updating the create_or_update method to conditionally use the new system metadata operation based on the presence of continuation tokens.
• Adding a new private helper method (_begin_create_or_update_model_with_system_metadata) to handle the create/update process using system metadata.

Comments suppressed due to low confidence (1)

sdk/ml/azure-ai-ml/azure/ai/ml/operations/_model_operations.py:353

• [nitpick] Consider defining a named constant for the accepted async status code (202) to improve readability and maintainability.

if response.status_code not in [202]:

[azure-sdk]

API change check

APIView has identified API level changes in this PR and created following API reviews.

azure-ai-ml

[achauhan-scc]

Http interactions are happening inside rest client layer, please follow the same pattern.