Add ROCm pytest workflow to nightly/release CI
Integrates the pytest_rocm.yml workflow into the main CI pipeline for nightly
and release testing. The workflow tests ROCm functionality across multiple GPU
configurations (1/4 GPUs), Python versions (3.11, 3.12), and Ubuntu
versions (22, 24).
Test configuration: JAX 0.9.0, ROCm 7.2.0, GitHub release tag rocm-jax-v0.9.0-rc.
