MILABL-6766 Fix rapids env issues for non docker envs - #104

Greptile Summary

The PR repairs RAPIDS environment creation on native backends by avoiding expression-renderer interpretation of ${PATH}, and explicitly packages a RAPIDS-compatible PyArrow release for targets where CUDA packages are skipped.

• RAPIDS runenv — the Python environment containing NVIDIA RAPIDS libraries; its PATH declaration now uses $PATH so native environment rendering does not interpret {PATH} as an undefined expression.
• envVars — environment-variable declarations shared by Docker and native runenv consumers; the PATH entry changes from ${PATH} to $PATH.
• PyArrow — Python bindings for Apache Arrow; version 19.0.1 is added as a direct packaged dependency for all configured targets.
• Package skip rules — platform mappings that omit unsupported CUDA packages; they are unchanged, while the newly direct PyArrow dependency remains available on non-CUDA targets.
• Changeset — release metadata describing a package update; a patch changeset documents both fixes and their compatibility rationale.

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