[JAX] Add NLTK pin <3.10.1 in encoder requirements

[aybchan]

Follow up to #3306, nvbug 6553963

[greptile-apps]

Greptile Summary

This PR constrains the JAX encoder example to NLTK versions below 3.10.1.

• Changes the supported NLTK range from >=3.8.2 to >=3.8.2,<3.10.1.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
examples/jax/encoder/requirements.txt	Adds the intended NLTK upper bound without an eligible follow-up defect.

_{Reviews (2): Last reviewed commit: "Add NLTK pin <3.10.1 in encoder requirem..." | Re-trigger Greptile}