Do not crash the client if ingestion server is down

[vizath]

Recently, we had received a few 503 from axiom logging.
When the Client receives a 503 after few retries, it raise an Exception.
That's problematic because it also crashes the whole app.

How to reproduce in a production python app:

• update your logger with a 503 error: axiom_py.Client(token=token, url_base="https://httpstat.us/503")
• Have a FastAPI endpoint creating a log
• See the logging crashing the route

Another solution would be to move the try/except in the flush function of logging.py.

I'm not super fluent in python, feel free to propose changes.

Some related stack trace:

Exception in thread Thread-8:
Traceback (most recent call last):
  File "/usr/local/lib/python3.12/threading.py", line 1075, in _bootstrap_inner
    self.run()
  File "/usr/local/lib/python3.12/threading.py", line 1433, in run
    self.function(*self.args, **self.kwargs)
  File "/usr/local/lib/python3.12/site-packages/axiom_py/logging.py", line 67, in flush
    self.client.ingest_events(self.dataset, local_buffer)
  File "/usr/local/lib/python3.12/site-packages/axiom_py/client.py", line 262, in ingest_events
    return self.ingest(
           ^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/axiom_py/client.py", line 239, in ingest
    res = self.session.post(
          ^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/requests/sessions.py", line 637, in post
    return self.request("POST", url, data=data, json=json, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/requests_toolbelt/sessions.py", line 76, in request
    return super(BaseUrlSession, self).request(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/requests/sessions.py", line 589, in request
    resp = self.send(prep, **send_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/requests/sessions.py", line 710, in send
    r = dispatch_hook("response", hooks, r, **kwargs)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/requests/hooks.py", line 30, in dispatch_hook
    _hook_data = hook(hook_data, **kwargs)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/axiom_py/client.py", line 182, in <lambda>
    "response": lambda r, *args, **kwargs: raise_response_error(r)
                                           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/axiom_py/client.py", line 145, in raise_response_error
    raise AxiomError(res.status_code, error_res)
axiom_py.client.AxiomError: API error 404: Not Found