Re-raise original exception in TF installation check logic.
Re-raise original exception in TF installation check logic.

Previously we were catching the underlying exception and raising a new one with a message about installing TF. This potentially masks other causes for a failure to import TF. Instead, this change makes it such that we simply print the informative message about installing TF, then reraise the original exception.

PiperOrigin-RevId: 231642916

tensorflow/probability,tensorflow/probability