fix: logos improvements

[raphael0202]

• don't include logos from deleted images in API routes (when it makes sense not to return them)
• delete logo embeddings (from ES and in DB), logos and image predictions of deleted images
• improve documentation

[codecov]

Codecov Report

Merging #1286 (24c62c9) into main (56d7fe2) will increase coverage by 0.07%.
The diff coverage is 86.36%.

@@            Coverage Diff             @@
##             main    #1286      +/-   ##
==========================================
+ Coverage   56.67%   56.74%   +0.07%     
==========================================
  Files          78       78              
  Lines        7569     7586      +17     
==========================================
+ Hits         4290     4305      +15     
- Misses       3279     3281       +2     

Files	Coverage Δ
robotoff/app/core.py	91.07% <100.00%> (ø)
robotoff/images.py	45.09% <100.00%> (+8.01%)	⬆️
robotoff/logos.py	41.37% <100.00%> (+1.02%)	⬆️
robotoff/app/api.py	48.36% <0.00%> (-0.24%)	⬇️

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