get_gemini_client() returns None.

[aero]

When running the following example,

$ curl -X 'POST'   'http://localhost:6969/v1/chat/completions'   -H 'accept: application/json'   -H 'Content-Type: application/json'   -d '{
  "model": "gemini-1.5-pro",
  "messages": [{ "role": "user", "content": "Hello!" }]
}'

[RESPONSE]
{"detail":"Gemini client is not initialized."}

When I execute "poetry run python src/run.py",
The starting server log indicates that the gemini_client has been initialized,
but on the following line, the get_gemini_client returns None.
https://github.com/Amm1rr/WebAI-to-API/blob/master/src/app/endpoints/chat.py#L51

It seems likely that there is a timing issue with object creation, or that the uvicorn web server does not share objects internally between processes or threads.

[Amm1rr]

Completed #49