add get_out_bias for linear atomic model

[github-actions]

Line: 310

deepmd-kit//deepmd/pt/model/atomic_model/linear_atomic_model.py

Lines 307 to 317 in e47478f

	def get_out_bias(self) -> torch.Tensor:
	"""Return the weighted output bias of the linear atomic model."""
	# TODO add get_out_bias for linear atomic model
	raise NotImplementedError
	def get_dim_fparam(self) -> int:
	"""Get the number (dimension) of frame parameters of this atomic model."""
	# tricky...
	return max([model.get_dim_fparam() for model in self.models])