Deprecate azure-ai-generative partially

[pamelafox]

Purpose

This logs an error when you try to run the generate script that relied on now deprecated QADataGenerator.

Does this introduce a breaking change?

[X] Yes - somewhat, yes, though the dependency upgrade already broke it
[ ] No

Pull Request Type

What kind of change does this Pull Request introduce?

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

How to Test

• Run summary CLI