Update text-gen v2 NB and add chat completion one

[novaturient95]

Description

• Updated text-gen v2 notebook
• added a chat completion one with working payload

Checklist

• [x] I have read the contribution guidelines
• [x] Pull request includes test coverage for the included changes.

[skasturi]

Please ensure the gates pass.

Is this notebook being ran as part of automated builds?

[novaturient95]

Please ensure the gates pass. Is this notebook being ran as part of automated builds?

gates are passed now. I don't think any of the foundational notebook workflows are currently run as automation. @HrishikeshGeedMS @jeff-shepherd could you confirm?

[praveenmathamsetty]

Could you share the NB test results?