Use the standard flow for blind signing

[spalmer25]

Here is how app-ethereum handle blind_signing:

---Screen 1---
<Warning-icon>
This transaction cannot be trusted

---Screen 2--- Not on Nanos
Your Ledger cannot decode this transaction. If you sign it, you could

---Screen 3--- Not on Nanos
be authorizing malicious actions that can drain your wallet.

---Screen 4---
Learn more: ...

---Screen 5---
<Accept-icon>
Accept risk and review transaction

---Screen 6---
<Reject-icon>
Reject

Currently, here is how the Tezos Wallet app handle blind_signing:

---Screen 1---
Parsing error
Reason

---Screen 2---
<Accept-icon>
Switch to blindsigning

---Screen 3---
<Reject-icon>
Reject

[spalmer25]

Ethereum

Nanos:

Nanosp / Nanox:

Current Tezos

Nanos:

Nanosp / Nanox: