Improve error handling

[ademar111190]

I need help testing iOS to check if this case https://github.com/breez/breezmobile/issues/978 is correctly covered.

The other two know cases (https://t.me/breez_lightning/25393 and one I have experienced myself) are correctly inserted, and I did add unit tests to help add future additions.

This structure allows us to add more exception message extraction improvements and be used by other parts of the app.