Bump rfdetr to 1.6.1

[Borda]

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

[Copilot]

Pull request overview

Updates the conda-forge recipe to package the latest rfdetr PyPI release by bumping the version and aligning the source checksum.

Changes:

• Bump rfdetr from 1.6.0 to 1.6.1.
• Update the sha256 for the new 1.6.1 source tarball.

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[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/recipe.yaml) and found it was in an excellent condition.