Add choice screen when pressing on "Reject" in transaction reviews (Stax / Flex)

[agrojean-ledger]

When pressing the "Reject" button to reject a transaction, it should trigger the "Reject or go back to transaction" screen instead of the notification directly.

Only for Stax and Flex.

There have been a few important changes in the NBGL module of the latest Rust SDK that should allow to fix this issue :

• The automatic status messages that were displayed when a user confirms / rejects a review have been removed.
• New APIs have been added to the NBGL module to allow developers to manually add them : NbglReviewStatus and NbglStatus. This change is especially important so that status screens are only displayed when the reply APDUs have actually been sent by the app (cf. boilerplate app and updated Rust SDK examples).
• A new API, NbglChoice has also been added to allow a developer to display a choice screen when the user performs an action (so in your case when the user presses the "Reject" button of a review). I have created a PR in the Rust SDK to add an example of how to implement the required flow