[FEATURE] google-auth as optional dependency

[amacal]

Problem Statement
I noticed a surprising dependency to google-auth in my poetry.lock file, which was derived from the databricks-sdk package. I see it was introduced here:

databricks-sdk-py/CHANGELOG.md

Line 1083 in 7a49922

* Introduced "google-auth" dependency to support Google authentication.

Proposed Solution
I am wondering if this google-auth dependency could be made optional for those who really want to use google authentication.

Additional Context