Set Duress PIN: Make more clear that user needs to login first

[myxmaster]

Describe your enhancement idea

When a PIN was set and user now wants to set a Duress PIN, Zeus just asks to "Enter PIN" (default PIN Lockscreen). While it totally makes sense to require existing PIN from user before setting a Duress PIN, users might not be aware and think they can immediately enter a Duress PIN at this point.

No big deal, but it would be better if in this case Zeus would ask to "Enter existing PIN" to avoid users to enter a wrong PIN first (because they are trying to create a Duress PIN).