Allow seeing ingredient parsing and ingredient diff before saving

[teolemon]

Problem

• Currently, you need to save the ingredient list to see how good it is parsed, and you can't see the Diff when you re-extract the OCR.

Proposed solution

• Show the diff between the saved ingredient list and the current list in real time (client side computation)
• Show the ingredient parsing on click on a "Preview parsing" button (using the API developed for Contribalim)

Time per product

1 to 3 mins

Mockups

Part of

• 🐣 Road to contribution / First time experience #5708
• ✏️ Editing (Tracker) #5525