feat: bump llama-stack to 0.3.0rc3+rhai0 (backport #104)

[mergify]

What does this PR do?

This PR bumps LLS version to upstream v0.3.0rc2 tag.

https://github.com/opendatahub-io/llama-stack/releases/tag/v0.3.0rc2%2Brhai0

Relates to: RHAIENG-1685

Closes https://issues.redhat.com/browse/RHAIENG-1685

Summary by CodeRabbit

• Chores

  • Switched to a git-based Llama Stack pre-release, added an env flag to temporarily disable version checks, added einops/safetensors/tokenizers, and removed ibm_watsonx_ai.

• Documentation

  • Updated distribution docs and build tooling to reference the Open Data Hub Llama Stack pre-release and adjusted version-detection behavior.

• Tests

  • Enabled stricter shell tracing, added a required-config pre-check, expanded test-skip logic, and constrained integration runs to a matching client version.

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This is an automatic backport of pull request #104 done by [Mergify](https://mergify.com).

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