This removes the hard-coded installation of osk-sdl when specifying
--fde (or using the on-device installer) and instead determines the
unlocker package by taking the most suitable provider of
postmarketos-fde-unlocker (factoring provider priority and packages
selected for installation).
With this change applied, one can manually select an unlocker package to
be installed via
pmbootstrap install --fde --add other-unlocker
Relates to: postmarketOS/pmaports#1309
2ad5427126