Add asset id none check in dt

[Pratibha Shrivastav (PratibhaShrivastav18)]

Description

Adding asset id none check in deployment template to avoid wrong dt detections

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All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

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[Copilot]

Pull request overview

This PR updates the Azure ML deployment default deployment template detection/logging to avoid reporting a template when the registry model’s default_deployment_template.asset_id is missing (None).

Changes:

• Tightened the check_default_deployment_template condition to require a non-None/truthy asset_id before logging template details.
• Minor import reordering/cleanup within _endpoint_utils.py.
• Added a corresponding bug-fix entry to the package changelog.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
sdk/ml/azure-ai-ml/azure/ai/ml/_utils/_endpoint_utils.py	Ensures default deployment template info is only logged when asset_id is present.
sdk/ml/azure-ai-ml/CHANGELOG.md	Documents the bug fix in the unreleased changelog.