fix: 7623 - cleaner UI/UX for price adding

[monsieurtanuki]

What

The latest version of the price adding introduced inconsistencies and removed features.
This PR fixes the most obvious problems:

• removal of the redundant "number of products" from the amount card, as it's already there twice in the page
• removal of the inconsistent "total price" from the amount card, as functionally it cannot be computed
• addition of the discount type drop down button, that was accidentally removed
• removal of the "location after image" business rule, as it was inconsistent with the "but you can add products regardless" apparent rule
• removal of the additional "add product" FAB, that was overlapping with the "send prices" FAB

Screenshots

a	b

Fixes bug(s)

• Fixes: Bad UI/UX for price adding #7623

Files

Deleted files:

• price_add_product_button.dart
• price_amount_quantity.dart
• price_amount_sum.dart

Impacted files:

• app_localizations.dart: wtf
• price_amount_card.dart: removed redundant and incorrect data
• price_amount_card_item.dart: put back the discount type drow down button
• price_location_card.dart: removed the inconsistent "no edit" mode
• product_price_add_page.dart: removed the additional "add" FAB

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 19 lines in your changes missing coverage. Please review.
✅ Project coverage is 9.06%. Comparing base (4d9c7fc) to head (06253a4).
⚠️ Report is 1463 commits behind head on develop.

Files with missing lines	Patch %	Lines
...h_app/lib/pages/prices/product_price_add_page.dart	0.00%	8 Missing ⚠️
...ooth_app/lib/pages/prices/price_location_card.dart	0.00%	6 Missing ⚠️
...h_app/lib/pages/prices/price_amount_card_item.dart	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           develop   #7625      +/-   ##
==========================================
- Coverage     9.54%   9.06%   -0.49%     
==========================================
  Files          325     646     +321     
  Lines        16411   37511   +21100     
==========================================
+ Hits          1567    3399    +1832     
- Misses       14844   34112   +19268     

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[teolemon]

I liked that they mirror a physical receipts, where those are usually visible at the end:
removal of the redundant "number of products" from the amount card, as it's already there twice in the page
removal of the inconsistent "total price" from the amount card, as functionally it cannot be computed

[monsieurtanuki]

Thank you @teolemon for your review!

Regarding the number of prices, it's not the number of items purchased as in a receipt: we don't support the number of items bought.
And again, we cannot compute the total price without number of items or with per-kg prices.