feat: A valid product needs to have a photo (otherwise -> new)

[g123k]

Hi everyone!

If a product is found on the server BUT doesn't have photos, it's considered as new.
It was initially planned with the new design, but we can implement it with the current code.

Video: https://github.com/user-attachments/assets/f45b44ad-c4bf-4ba8-8621-e58875c1b05e

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 20 lines in your changes missing coverage. Please review.

Project coverage is 6.27%. Comparing base (4d9c7fc) to head (fc29b16).
Report is 649 commits behind head on develop.

Files with missing lines	Patch %	Lines
...oth_app/lib/data_models/continuous_scan_model.dart	0.00%	12 Missing ⚠️
...es/smooth_app/lib/data_models/fetched_product.dart	0.00%	3 Missing ⚠️
...ib/pages/product/common/product_dialog_helper.dart	0.00%	2 Missing ⚠️
...th_app/lib/pages/search/search_product_helper.dart	0.00%	2 Missing ⚠️
...oth_app/lib/pages/scan/carousel/scan_carousel.dart	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           develop   #6191      +/-   ##
==========================================
- Coverage     9.54%   6.27%   -3.28%     
==========================================
  Files          325     456     +131     
  Lines        16411   26309    +9898     
==========================================
+ Hits          1567    1651      +84     
- Misses       14844   24658    +9814     

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[teolemon]

I need to think a little bit on this one:

• Does this work if you're not logged in ?
• Should we push people in the pipeline if we have no score for food in general?
• Should we push people in the pipeline if we have badly outdated photos ?
• Should we integrate Robotoff in editing screens (since pre-computation will already be done in some cases, like category prediction, and even more if we adopt this behaviour more broadly)
• How do we add cases safely while handling well edge cases.