There are Chinese characters in my project, but after calling the visualize_document_datamap() method, the characters appear as garbled text.

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### Desribe the bug

fig = topic_model.visualize_document_datamap(
sentences,
topics=topics,
reduced_embeddings=reduced_embeddings,
#custom_labels=custom_labels,
title='文档和主题的分布',
sub_title='基于 BERTopic 的主题建模',
width=1200,
height=1200
)
Even after setting
plt.rcParams['font.sans-serif'] = ['SimHei'],
I still can't see the characters.

### Reproduction

```python
from bertopic import BERTopic
# with the reduced embeddings
reduced_embeddings = UMAP(n_neighbors=15, n_components=2, min_dist=0.0, metric='cosine').fit_transform(embeddings)
fig = topic_model.visualize_document_datamap(
sentences,
topics=topics,
reduced_embeddings=reduced_embeddings,
#custom_labels=custom_labels,
title='文档和主题的分布',
sub_title='基于 BERTopic 的主题建模',
width=1200,
height=1200
)
```

### BERTopic Version

0.16.4

Start at the BERTopic visualize_document_datamap() entry point and run the supplied reproduction with the Chinese title and subtitle. Trace how text is rendered and compare it with the attempted matplotlib font configuration. Done means Chinese characters in the visualization display correctly instead of as garbled text.

Written by the indexing model from the issue text.