Update sd3 controlnet example

[DavyMorgan]

What does this PR do?

This is a follow-up PR for #9249 to use the make_image_grid() utility function from diffusers.utils and use checkpoint on the Hub.

Fixes # (issue)

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[DavyMorgan]

@sayakpaul Hi, in this PR I further update the codes per your suggestion in #9249 (review)

[sayakpaul]

Thank you!

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