Add extra safety prompt before showing mnemonic

[aguycalled]

Before showing the mnemonic, an extra safety prompt must be shown:

You are going to be shown a list of 12 words, known as mnemonic.

A mnemonic is a private key that is not protected by any encryption measures. Once someone gets your mnemonic, it is equivalent to controlling your wallet. Keep the mnemonics safe, do not store them in online devices and do not lose it.

Please be sure noone is around looking at your screen and tap here to show the mnemonic.

[tsejerome]

I think we shd ask the user to readPassword at the same time too

[aguycalled]

I think it should be reading the password already, otherwise it can't decrypt the mnemonic

[tsejerome]

Just checked the code, when we visit mnemonic screen it doesn't prompt that, I think it is decrypted whenever we have an opened wallet, basically its like re-authing when we send transaction