Validação de erros ao gerar alt text das imagens

[guites]

Ao chamar o endpoint do alt text, por vezes a API retorna um 503:

[2025-09-10 14:45:04,258] ERROR in app: Exception on /screening/image/describe [POST]
Traceback (most recent call last):
  File "/usr/local/lib/python3.10/site-packages/flask/app.py", line 1473, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/local/lib/python3.10/site-packages/flask/app.py", line 882, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/local/lib/python3.10/site-packages/flask/app.py", line 880, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python3.10/site-packages/flask/app.py", line 865, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)  # type: ignore[no-any-return]
  File "/app/flask_backend/routes/auth.py", line 102, in wrapped_view
    return view(**kwargs)
  File "/app/flask_backend/routes/screening.py", line 453, in describe_image
    prompt_response = gemini.prompt_image(image, prompt_text)
  File "/app/flask_backend/service/gemini_api.py", line 47, in prompt_image
    r.raise_for_status()
  File "/usr/local/lib/python3.10/site-packages/requests/models.py", line 1021, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 503 Server Error: Service Unavailable for url: https://generativelanguage.googleapis.com/v1beta/models/gemini-1.5-flash-latest:generateContent?key=AIzaSyDDjl2xywQPpqHZ_LLtix32alepDxQdZ-k

Adicionar uma validação desse erro, pois geralmente funciona se chamar o endpoint uma segunda vez.