Temporarily limit fastapi to less than 0.118.0 to fix CI

[amoghrajesh]

Fastapi 0.118 introduces a breaking change that breaks our CI: https://github.com/apache/airflow/actions/runs/18116283428

• Previously (≤0.117), the yield dependency cleanup code (e.g., closing a create_session context manager in _get_session) ran before the response was sent.
• In 0.118.0+, the cleanup now runs after the response starts streaming.
• This means exceptions (like duplicate entity errors when the DB session commits implicitly) are raised too late → response has already started, so FastAPI can’t change the status code ("Caught handled exception, but response already started.").

Next steps is to raising this with Sebastián (FastAPI maintainer) since this was an intentional change to support streaming responses, and he has signaled awareness that it could cause issues and synchronise and resolve the issue.

related: https://www.linkedin.com/posts/tiangolo_advanced-dependencies-fastapi-activity-7378282080457187328-ZTT_?utm_source=share&utm_medium=member_desktop&rcm=ACoAAAAbPJABWNiWtLGbVPUKL8PDTSlmqJVvFTs

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[amoghrajesh]

Mypy issue fixed by #56244

[jamie-albert]

Greetings, if I may leave this here to make the path easier for those who follow

1. Upstream discussion: [0.118.0] Use case for early closing in yield dependencies (session commit before response) fastapi/fastapi#14151