[ci] Remove default value & use environment variables for release automation pipeline

[khluu]

Changes

• Eliminate use of default value for RAY_VERSION and RAY_HASH to ensure that correct version is manually put in and sanity checked.
• Remove default value for Python version.
• Export env variables to linux sanity check script.

Checks

• Build passed on Buildkite with ray version & hash set to 2.9.2 : https://buildkite.com/ray-project/release-automation/builds/116