Ensure we handle all offline situations correctly (tracker)

### What
- This app heavily relies on a network connection, we should test how the app behaves when there is no internet connection and even if there are no crashes we should still somehow indicate that there are some connection issues.
- Something like this is probably already enough 
  - https://www.fluttercampus.com/guide/1/flutter-automatically-show-internet-connection-message-on-offline-or-online/

### List of features


```[tasklist]
### Tasks
- [ ] #413
- [ ] Handle unexpected server responses well (Ensure 404,502, SSL issues don't crash anything)
- [x] Ensure caching of all viewed products
- [x] Ensure that all products in Product history are stored for offline viewing
- [x] Ensure that all products already opened are viewable offline
- [ ] Change preferences
- [ ] #18
- [ ] #1235
- [x] Ensure that we use Android (and potentially iOS)  load and notify me as soon we get network webview mechanism when we attempt to load pages offline
- [ ] https://github.com/openfoodfacts/smooth-app/issues/4065
- [ ] Change the ugly offline wifi icon placeholder for images
- [ ] https://github.com/openfoodfacts/smooth-app/issues/4064
```

### Part of
- #525 

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Ensure we handle all offline situations correctly (tracker) #863

M123-dev
openedon Jan 5, 2022

What

List of features

Tasks

Part of

Assignees

Labels

Type

Projects

Milestone

Relationships

Development