[Data] Bump batch_inference_hetero timeout

[bveeramani]

Why are these changes needed?

#49012 decreased number of GPUs for batch_inference_hetero from 40 to 10. As a result, the test has been timeing out. This PR fixes the test by bumping up the timeout.

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  • This PR is not tested :(

[srinathk10]

LGTM!