Explicitly convert ndarray to tf tensor in bsuite/baselines/tf/dqn.
Explicitly convert ndarray to tf tensor in bsuite/baselines/tf/dqn.

PiperOrigin-RevId: 317468868
Change-Id: I71b2fdd636cc40df6d035b1c4f7fd0997f81d4c5

deepmind/bsuite,deepmind/bsuite