Support Azure OpenAPI in MongoDB integration tests

[blink1073]

Description

We (MongoDB) have been running the integration tests nightly for llama-index-vector-stores-mongodb. We have had to switch from using OpenAPI keys directly to using Azure OpenAPI credentials. This PR updates the integration tests to accommodate either.

Addresses https://jira.mongodb.org/browse/INTPYTHON-669.

Type of Change

Update of integration tests for llama-index-vector-stores-mongodb.

How Has This Been Tested?

Tested with our integration testing pipeline, mongodb-labs/ai-ml-pipeline-testing#94.

Suggested Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added Google Colab support for the newly added notebooks.
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I ran uv run make format; uv run make lint to appease the lint gods