ci: Fix/Improve L0_openai_trtllm test

[krishung5]

What does the PR do?

Replaced Triton CLI usage in the test with TRTLLM tooling for less maintenance effort.

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• build
• ci
• docs
• feat
• fix
• perf
• refactor
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• test

Related PRs:

MR 413

Where should the reviewer start?

Test plan:

• CI Pipeline ID: 22617636

Caveats:

Background

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• closes GitHub issue: #xxx

[rmccorm4]

Nice changes Kris! Hopefully this test is more flexible across TRT-LLM images and less dependent on CLI updates for now.