Importing SaasFullyBayesianSingleTaskGP into fit (#2705)

Summary:
Pull Request resolved: #2705

Correcting land-time race condition that caused BoTorch to break on main today.

Reviewed By: esantorella

Differential Revision: D68727226

fbshipit-source-id: b97f52a8480acec0984a94f9313298c27eea26eb

Author: SebastianAment

botorch/fit.py

@@ -22,7 +22,10 @@
 from botorch.logging import logger
 from botorch.models import SingleTaskGP
 from botorch.models.approximate_gp import ApproximateGPyTorchModel
-from botorch.models.fully_bayesian import FullyBayesianSingleTaskGP
+from botorch.models.fully_bayesian import (
+    FullyBayesianSingleTaskGP,
+    SaasFullyBayesianSingleTaskGP,
+)
 from botorch.models.fully_bayesian_multitask import SaasFullyBayesianMultiTaskGP
 from botorch.models.map_saas import get_map_saas_model
 from botorch.models.model_list_gp_regression import ModelListGP