Update description on Export Recovery Backup UI

[nicoletting]

Before: In oder to export your mnemonic properly, we need a password with it will be encrypted for security reasons. Please insert below passwords that you will also be required later when importing it.

After: To properly export your recovery phrase, it requires a password which is encrypted for security. Please enter the password required for importation.

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Before: You can export this data whenever you want, even sending it to a friend of yours for backup, if you have used a strong enough password.

After: If you use a strong protective password, you can export this data at any time and send it to a friend for backup.

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Change the word " tweet" to "Twitter"

UI is ready View prototype here