Refactor: Update deprecated logger.warn to logger.warning

[wei-juncheng]

What type of PR is this?

• [x] Refactor
• [ ] Feature
• [ ] Bug Fix
• [ ] Other

Description

• Modify the usage of the deprecated logger method.
  • src/databricks/sql/thrift_backend.py:
    • Use logger.warning instead of logger.warn.

How is this tested?

• [x] Unit tests
• [ ] E2E Tests
• [ ] Manually
• [ ] N/A