feat: Tagline: support "min_launches" attribute

[g123k]

Hi everyone!

We have complaints about the donation campaign from new users (= asked too early).
News in the tagline can now provide a min_launches attribute = min launches of the app.

cf https://github.com/openfoodfacts/smooth-app_assets/pull/8/files

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 25.00000% with 12 lines in your changes missing coverage. Please review.

Project coverage is 6.21%. Comparing base (4d9c7fc) to head (43b2015).
Report is 674 commits behind head on develop.

Files with missing lines	Patch %	Lines
...h_app/lib/data_models/news_feed/newsfeed_json.dart	0.00%	9 Missing ⚠️
...p/lib/data_models/news_feed/newsfeed_provider.dart	0.00%	2 Missing ⚠️
..._app/lib/data_models/news_feed/newsfeed_model.dart	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           develop   #6236      +/-   ##
==========================================
- Coverage     9.54%   6.21%   -3.34%     
==========================================
  Files          325     456     +131     
  Lines        16411   26716   +10305     
==========================================
+ Hits          1567    1660      +93     
- Misses       14844   25056   +10212     

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