device: Load the current finger print and not always the first print
In the garbage collection code we always ended up to load the first enrolled print, and this may lead to removing from device storage prints that are actually in use.
@benzea I thought about merging this when squashed with the coming function (2d7ef57c - as I discovered while testing it), but having this fix first makes it easier to cherry-pick for distro patching.
Btw... Virtual MoC device is needed, as this was one of the few codepaths not checked...