We should make bier import optional , we currently fail in an environment without beir because of below import:

https://github.com/NVIDIA-Merlin/crossfit/blob/3965dda2d6312fc7572a7917771b8afc3e9176a4/crossfit/backend/torch/op/vector_search.py#L3C1-L3C1

We should switch that to an optional dependency.