The device drying options hold several values per filament, as many as
the filament preset gives, and a project stores them as the filaments'
values one after another. The CLI filament merge wrote them like an
option with one value per filament, putting each preset's first value at
the filament's own index, so a project with three filaments whose preset
gives "1", "0" was exported with 1;1;1;0;1;0 where the GUI writes
1;0;1;0;1;0.
The merge now leaves these options out of the per-filament pass and
rebuilds them afterwards from every filament's values in slot order.
Without a fixed number of values per filament one slot cannot be
replaced in place, so the stored values are kept when any slot has no
config to rebuild from.