Update sample_agent_image_generation.py docs recommended image model

[ahibrahimm]

Description

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[Copilot]

Pull request overview

This PR updates the documentation in image generation sample files to recommend using "gpt-image-1" instead of "gpt-image-1-mini" as the image generation model. The change reflects a preference for the more capable model that supports additional features like high input fidelity settings.

Changes:

• Updated documentation comments to reference "gpt-image-1" instead of "gpt-image-1-mini" in both sync and async versions
• Modified inline code comments to reflect the new recommended model name

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
sdk/ai/azure-ai-projects/samples/agents/tools/sample_agent_image_generation_async.py	Updated documentation to recommend "gpt-image-1" model in comments
sdk/ai/azure-ai-projects/samples/agents/tools/sample_agent_image_generation.py	Updated documentation to recommend "gpt-image-1" model, but also contains unintended changes to agent_name and commented-out cleanup code

[Copilot]

The README.md file still references "gpt-image-1-mini" in the image generation example snippet (line 265), but this PR updates the sample files to recommend "gpt-image-1" instead. For consistency across the documentation, the README should also be updated to reflect this new recommendation.

[dargilco]

Can you please also delete this sentence? clearly no longer needed if the samples work for you without the header.
"as well as providing it in the x-ms-oai-image-generation-deployment header when calling .responses.create."

[ahibrahimm]

I haven't tried it without this header actually, let me give it a test

[ahibrahimm]

I think we still need the header, it failed just now when I ran it without it