feat: 3897 - ingredients and packaging with multilingual OCR image+text

[monsieurtanuki]

What

• This PR refactors the multilingual management already in place for product name in "Add basic details" page.
• This PR also use that same multilingual management in the OCR pages (ingredients and packaging).
• It looks successful on ingredients (e.g. for products 7300400481588 or 3760091722508)
• But I'm afraid that there are currently no such things as multilingual packagings (cf. 'packaging_text_languages') on the server - at least I couldn't find an example.
• For ingredients, I had to add a product field ('ingredients_text_languages'): if you don't see the language selector in the ingredients OCR page, please refresh the product first.
• As for packaging, unless you find a product with multilingual packaging on the server, you won't be able to find the language selector on the OCR page.

Screenshots

App in French, on the ingredient OCR page, by default with the French settings:

French text before OCR	French text after OCR

Same app in French, on the ingredient OCR page, after setting the page language to Italian:

Italian text before OCR	Italian text after OCR

Part of

• Multilingual images #3897

Files

New file:

• multilingual_helper.dart: Helper for multilingual inputs (e.g. product name).

Deleted file:

• ocr_widget.dart: moved code to edit_ingredients_page.dart, for better state refresh

Impacted files:

• add_basic_details_page.dart: refactored with new class MultilingualHelper
• edit_ingredients_page.dart: added multilingual management; moved code from ocr_widget.dart
• ocr_helper.dart: refactored with multilingual management
• ocr_ingredients_helper.dart: refactored with multilingual management
• ocr_packaging_helper.dart: refactored with multilingual management
• product_query.dart: added multilingual ingredients field; removed duplicate field

[codecov-commenter]

Codecov Report

Merging #3911 (44c33d3) into develop (4e9349c) will decrease coverage by 0.02%.
The diff coverage is 0.00%.

@@             Coverage Diff             @@
##           develop    #3911      +/-   ##
===========================================
- Coverage    10.66%   10.64%   -0.02%     
===========================================
  Files          271      271              
  Lines        13455    13478      +23     
===========================================
  Hits          1435     1435              
- Misses       12020    12043      +23     

Impacted Files	Coverage Δ
..._app/lib/pages/product/add_basic_details_page.dart	0.00% <0.00%> (ø)
...h_app/lib/pages/product/edit_ingredients_page.dart	0.00% <0.00%> (ø)
...oth_app/lib/pages/product/multilingual_helper.dart	0.00% <0.00%> (ø)
...kages/smooth_app/lib/pages/product/ocr_helper.dart	0.00% <ø> (ø)
..._app/lib/pages/product/ocr_ingredients_helper.dart	0.00% <0.00%> (ø)
...th_app/lib/pages/product/ocr_packaging_helper.dart	0.00% <0.00%> (ø)
packages/smooth_app/lib/query/product_query.dart	8.10% <ø> (ø)

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[teolemon]

Here's a product with several languages: https://world.openfoodfacts.org/api/v0/product/5400141625714.json

[monsieurtanuki]

Hi @teolemon, and thank you for your comment and example.

As far as I'm concerned, the PR seems to work too for multilingual packaging. But:

1. the image was not relevant for OCR, therefore it failed (in French)
2. my smartphone does not support the other language, that was Afar, and therefore the language could not appear as pre-selected as it virtually does not exist (at least for my smartphone) (for the record 76 off languages are recognized and 107 rejected) (feel free to open an issue if relevant)
3. I managed to add a translation (directly, no OCR), in Dutch

language selector with only French	failed OCR in French	input in Dutch

https://fr.openfoodfacts.org/api/v3/product/5400141625714?lc=fr&fields=packaging_text_languages

{
	"code": "5400141625714",
	"errors": [],
	"product": {
		"packaging_text_languages": {
			"aa": "test afar",
			"fr": "test fr tanuki",
			"nl": "test nl tanuki"
		}
	},
	"result": {
		"id": "product_found",
		"lc_name": "Produit trouvé",
		"name": "Product found"
	},
	"status": "success",
	"warnings": []
}

[monsieurtanuki]

Thank you @teolemon for your approval: that's another step towards a fully multilingual app.