Add longtest decorator to pairwise model tests (#2731)

Summary:
Pull Request resolved: #2731

Sam fixed the logic in the test yesterday, thanks sam!, but now it's timing out this adds it to the backlog to be fixed.

Reviewed By: danielcohenlive, mpolson64

Differential Revision: D62036700

fbshipit-source-id: 7d35c777e77c87cc1d179e5e4e5af4745c69e7df

ax/modelbridge/tests/test_pairwise_modelbridge.py

@@ -38,6 +38,9 @@ def setUp(self) -> None:
         self.experiment = experiment
         self.data = experiment.lookup_data()
 
+    @TestCase.ax_long_test(
+        reason="TODO[T199510629] Fix: break up test into one test per case"
+    )
     def test_PairwiseModelBridge(self) -> None:
         surrogate = Surrogate(
             botorch_model_class=PairwiseGP,