Update DataBricks to Databricks and renamed environment variables (#12595)

...x-integrations/llms/llama-index-llms-databricks/README.md

...x-llms-databricks/llama_index/llms/databricks/__init__.py

...index-llms-databricks/llama_index/llms/databricks/base.py

...egrations/llms/llama-index-llms-databricks/pyproject.toml

...ndex-llms-databricks/tests/test_integration_databricks.py

...llama-index-llms-databricks/tests/test_llms_databricks.py