Fix JAX version bugs for nightly image

[hengtaoguo]

Description

Skip the JAX 0.7.0 installation for the nightly images. Only do so for the stable_stack used in GitHub CI.

b/451429959

Tests

N/A

Checklist

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[gobbleturk]

This may or may not fix the actual issue; transitive dependencies like tunix might still force a different jax version than we desire.

Regardless this PR looks like a strict improvement, thanks!