Can't update model name when use notebook

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I have a quick question: I use openai embedding to generate the text-embedding. I found I couldn't update the model name unless I restart the jupyter kernal. But it's ok when I switch to python (not jupyter). Here is an example code

```
import openai
from bertopic.backend import OpenAIBackend
client = openai.OpenAI(api_key="sk-xxxxx")
embedding_model = OpenAIBackend(client, 'text-embedding-3-large')
print(embedding_model.embedding_model)
```

Here is screenshot from notebook and python:

notebook:

python script:

The reported entry point is bertopic.backend.OpenAIBackend, demonstrated in the notebook snippet; compare its behavior in Jupyter with the Python script case. Reproduce changing the model name without restarting the kernel, then verify that embedding_model reflects the selected name.

Written by the indexing model from the issue text.