ubiquity prompts for a MOK password that it then does not use

When opting to install non-free drivers on my new laptop, ubiquity tells me that:

  Installing third-party drivers requires configuring Secure Boot. To do this,
  you need to choose a security key now, and enter it when the system restarts.

And it forces me to choose a password.

However, the only hardware on my system that has non-free drivers is nvidia; and thanks to linux-restricted-modules, it should not be necessary to use locally-built dkms modules for nvidia (but see also https://bugs.launchpad.net/ubuntu/+source/linux-restricted-modules/+bug/1856407).

I should not be prompted to create another password for a thing before we know it's actually going to be needed / used. This means ubiquity should know to only prompt for a password and invoke mokutil if proprietary drivers other than linux-modules-nvidia will actually be installed.

Also, note that the unlike ubiquity, dkms/shim-signed debconf handling of the secureboot does not use a 'password' field type. This is not a sensitive password that must be kept secret, it is only used to prove to MokManager when running from UEFI that the key enrollment request came from the person who has physical control of the hardware and is used one time, then discarded. So there's really no need to hide the text being entered in this field.