Completion call using openai sdk should use "deployment_name" not "model_name"

[alexmanie]

Purpose

Slightly change variable used during notebook testing calls to openai.

Does this introduce a breaking change?

[ ] Yes
[x] No

Pull Request Type

What kind of change does this Pull Request introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[x] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:

How to Test

Execute call to openai services through APIM using provided notebook.