BreakSim creates a StackSelection with count=0 to represent an empty
hand being acceptable. When the build engine resolved a WrongItemSelection
result with this selection, it unconditionally called transferByTask,
spawning a ContainerTransferTask that tried to move 0 items out of a
shulker box  which always failed with NoMaterialAccessException.

Two fixes:
- GenericResult.WrongItemSelection.resolve(): skip the transfer when
  count == 0, since nothing needs to be acquired.
- ContainerTransferTask.checkFail(): was calling failure() unconditionally
  via �lso {}, making failIfNoMaterial only affect the (unused) return
  value. Now correctly calls failure() only when failIfNoMaterial is true,
  and success() otherwise.