Add arg is_deprecated to RFDETRLarge class

[PierreMarieCurie]

What does this PR do?

Hello Roboflow team, this PR exposes the is_deprecated parameter of RFDETRLarge class so that we can access to the deprecated version of RFDETR-large. I am not able to tell if the non-exposure was intentional, so if it was, feel free to reject this PR.

Related Issue(s):

No related issue.

Type of Change

• New feature (non-breaking change that adds functionality)

Testing

from rfdetr.detr import RFDETRLarge
RFDETRLarge(is_deprecated=False)
RFDETRLarge(is_deprecated=True) 

This script above, with the current develop branch, loads the new version of RFDETR-large twice (rf-detr-large-2026.pth). The only way to load the old version (rf-detr-large.pth) is to use the RFDETRLargeDeprecated class or if loading the new version from the RFDETRLarge class fails. With my commit, we can access the deprecated version from the RFDETRLarge class.

• I have tested this change locally
• I have added/updated tests for this change

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code where necessary, particularly in hard-to-understand areas
• My changes generate no new warnings or errors
• I have updated the documentation accordingly (if applicable)

[PierreMarieCurie]

I have read the CLA Document and I sign the CLA.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 22%. Comparing base (35ac6ab) to head (3ca260e).
⚠️ Report is 21 commits behind head on develop.

❌ Your patch check has failed because the patch coverage (0%) is below the target coverage (95%). You can increase the patch coverage or adjust the target coverage.
❌ Your project check has failed because the head coverage (22%) is below the target coverage (95%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@          Coverage Diff           @@
##           develop   #621   +/-   ##
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  Coverage       22%    22%           
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  Files           46     46           
  Lines         6182   6182           
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  Hits          1343   1343           
  Misses        4839   4839           

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[Borda]

from rfdetr.detr import RFDETRLarge
RFDETRLarge(is_deprecated=False)
RFDETRLarge(is_deprecated=True) 

I feel like this adds more confusion there, helping... can you pls elaborate more on the user experience?