These changes are mainly to add flexibility to the auth service in
supporting azure authenticating via:

- A personal identity via az CLI for the local dev environment. This
will still run into expiring issues, but is probably fine for local dev.
- A personal or managed identity in an azure hosted environment. The
flexibility to use the managed identity allows us to avoid the expiring
issue without needing a separate SP, key-vault and cert setup, aligning
with new security recommendations.

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Co-authored-by: Eu Jing Chua <eujingchua@microsoft.com>
Co-authored-by: Sergiy Matusevych <sergiym@microsoft.com>

Mypy got updated to v 1.11 recently
We need these mypy fixes to make other PRs pass the CI tests

Closes microsoft#785 

Also, add more unit tests to make sure the optimizer handles string
inputs correctly.

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Co-authored-by: Brian Kroth <bpkroth@users.noreply.github.com>

…sergiym/opt/llamatune_inv