Update sentence_transformer_embedding_function.py

[louisbrulenaudet]

Description of changes

• Improvements & Bug fixes
  • Updated the encoding function to support modification of the batch_size to prevent memory errors on small GPUs or when using large models when the device is set to cuda.

Test plan

• [x] Tests pass locally with pytest for python.

Documentation Changes

• The new batch_size parameter is now available in the documentation.