We should be clearer about the ground cause for errors

[teolemon]

What

• We should be clearer about the ground cause for errors.

Why

• We have had server issues recently, and people commented in the play store that we didn't recognize any product, while this was really a server error.

Part of

• 🎯 What can I work on ? #525

Screenshot/Mockup/Before-After

[monsieurtanuki]

@teolemon If there's a "ping" on the server, we could use it to group "server down" with "no connection" on one side, and "the product was probably moved or deleted" as a fallback.

That would be a start. The next steps would be to know if the user has a connection (flutter side), and what the hell happened with this product (server request stating if a barcode was moved or deleted".

[monsieurtanuki]

• In order to check connectivity: https://pub.dev/packages/connectivity_plus (flutter favorite)
• For "ping", https://pub.dev/packages/dart_ping and https://pub.dev/packages/dart_ping_ios

[monsieurtanuki]

Related to #4425

[monsieurtanuki]

Fixed by #4423. Feel free to reopen if needed.