We don't want to use BnB when there are preset inputs because there
is some weirdness with making that work with using the KnapsackSolver
as the fallback. Currently we say that we haven't used bnb when
there are preset inputs, but we don't actually disable BnB. This fixes
that.
Test that BnB is not used when there are preset inputs
This is a backport of Core PR12694
Depends on D3364