Correct how apply_overlay read crop_coords

[rootonchair]

What does this PR do?

While working on #6360, I see that get_crop_region returns x1, y1, x2, y2 https://github.com/huggingface/diffusers/blob/main/src/diffusers/image_processor.py#L264
while apply_overlay reads it as x, y, w, h

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline?
• Did you read our philosophy doc (important for complex PRs)?
• Was this discussed/approved via a GitHub issue or the forum? Please add a link to it if that's the case.
• Did you make sure to update the documentation with your changes? Here are the
  documentation guidelines, and
  here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

[yiyixuxu]

thanks for the fix!