power bi api wrapper integration tests & bug fix

[eyurtsev]

Powerbi API wrapper bug fix + integration tests

• Bug fix by removing TYPE_CHECKING in in utilities/powerbi.py
• Added integration test for power bi api in utilities/test_powerbi_api.py
• Added integration test for power bi agent in agent/test_powerbi_agent.py
• Edited .env.examples to help set up power bi related environment variables
• Updated demo notebook with working code in docs../examples/powerbi.ipynb - AzureOpenAI -> ChatOpenAI

Notes:

Chat models (gpt3.5, gpt4) are much more capable than davinci at writing DAX queries, so that is important to getting the agent to work properly. Interestingly, gpt3.5-turbo needed the examples=DEFAULT_FEWSHOT_EXAMPLES to write consistent DAX queries, so gpt4 seems necessary as the smart llm.

Fixes #4325

Before submitting

Azure-core and Azure-identity are necessary dependencies

check integration tests with the following:
pytest tests/integration_tests/utilities/test_powerbi_api.py
pytest tests/integration_tests/agent/test_powerbi_agent.py

You will need a power bi account with a dataset id + table name in order to test. See .env.examples for details.

Who can review?

@hwchase17
@vowelparrot