[secure account] fix copy

[jellegerbrandy]

• remove "mnemonic" on the "insert your 12 word phrase" page
• What does this mean?: "It will work for a password for fast transactions, but only if you are logged in". Just remove it
• the password screen for "log in" says "new password" in the input field. Which is confusing, it should say "insert your password"
• "Key derivation failed - possibly wrong password" is too technical, should be "password is invalid"
• "We found a private wallet on your localStorage, insert the password to decrypt it, and be able to use all the features of Paratii" -> "Please insert your password to use all the features of Paratii"
• "Create a password for securing your account" -> "Choose a password"

[eliawk]

@jellegerbrandy i don't find the first one!