Added more warnings to only load trusted models

[svick]

This is a followup to #53999, which adds the same warning to more articles that mention loading ML.NET models.

Also fixes invalid code in deep-learning-overview.md.

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Internal previews

📄 File	🔗 Preview link
docs/machine-learning/deep-learning-overview.md	docs/machine-learning/deep-learning-overview
docs/machine-learning/how-to-guides/machine-learning-model-predictions-ml-net.md	docs/machine-learning/how-to-guides/machine-learning-model-predictions-ml-net
docs/machine-learning/how-to-guides/retrain-model-ml-net.md	docs/machine-learning/how-to-guides/retrain-model-ml-net
docs/machine-learning/how-to-guides/serve-model-serverless-azure-functions-ml-net.md	docs/machine-learning/how-to-guides/serve-model-serverless-azure-functions-ml-net
docs/machine-learning/how-to-guides/serve-model-web-api-ml-net.md	docs/machine-learning/how-to-guides/serve-model-web-api-ml-net
docs/machine-learning/tutorials/image-classification.md	docs/machine-learning/tutorials/image-classification
docs/machine-learning/tutorials/object-detection-custom-vision-onnx.md	docs/machine-learning/tutorials/object-detection-custom-vision-onnx
docs/machine-learning/tutorials/object-detection-onnx.md	docs/machine-learning/tutorials/object-detection-onnx
docs/machine-learning/tutorials/text-classification-tf.md	docs/machine-learning/tutorials/text-classification-tf

[Copilot]

Pull request overview

This PR extends the ML.NET security guidance that models should only come from trusted sources by adding [!IMPORTANT] warnings to additional tutorials and how-to guides. It also attempts to fix invalid code in deep-learning-overview.md by correcting the ONNX pipeline example.

Changes:

• Add “only load/apply trusted models” [!IMPORTANT] warnings across several ML.NET articles that demonstrate loading or applying pretrained models.
• Update the ONNX example in deep-learning-overview.md (but the TensorFlow and ONNX snippets still need corrections to be valid, per review comments).
• Add the same warning to model-serving guides (wording should be aligned with the established “load models” phrasing).

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
docs/machine-learning/tutorials/text-classification-tf.md	Adds an IMPORTANT warning before loading a pretrained TensorFlow model.
docs/machine-learning/tutorials/object-detection-onnx.md	Adds an IMPORTANT warning near the ApplyOnnxModel pipeline step.
docs/machine-learning/tutorials/object-detection-custom-vision-onnx.md	Adds an IMPORTANT warning before applying an ONNX model in the pipeline.
docs/machine-learning/tutorials/image-classification.md	Adds an IMPORTANT warning before loading/scoring with a TensorFlow model.
docs/machine-learning/how-to-guides/serve-model-web-api-ml-net.md	Adds an IMPORTANT warning before registering/loading a model for serving (needs wording consistency).
docs/machine-learning/how-to-guides/serve-model-serverless-azure-functions-ml-net.md	Adds an IMPORTANT warning before registering/loading a model for serving (needs wording consistency).
docs/machine-learning/how-to-guides/retrain-model-ml-net.md	Adds an IMPORTANT warning before loading a pretrained model.
docs/machine-learning/how-to-guides/machine-learning-model-predictions-ml-net.md	Adds an IMPORTANT warning before loading a model for predictions.
docs/machine-learning/deep-learning-overview.md	Adds an IMPORTANT warning and modifies the ONNX snippet (still needs fixes for correctness).