[hotfix] Fix examples/awel default loading model text2vec-large-chinese issue

[xiuzhu9527]

Description

When I set the parameter EMBEDDING_MODEL=bge-large-zh, an error occurs when starting the service
2024-01-19 17:51:55 172-16-10-163 dbgpt.core.awel.dag.loader[5422] ERROR Failed to import: /mnt/data/xiuzhu/DB-GPT/examples/awel/simple_rag_retriever_example.py, error message: Traceback (most recent call last):
File "/mnt/data/xiuzhu/DB-GPT/dbgpt/core/awel/dag/loader.py", line 86, in parse
loader.exec_module(new_module)
File "", line 883, in exec_module
File "", line 241, in _call_with_frames_removed
File "/mnt/data/xiuzhu/DB-GPT/examples/awel/simple_rag_retriever_example.py", line 91, in
vector_connector = _create_vector_connector()
File "/mnt/data/xiuzhu/DB-GPT/examples/awel/simple_rag_retriever_example.py", line 86, in _create_vector_connector
).create(),
File "/mnt/data/xiuzhu/DB-GPT/dbgpt/rag/embedding/embedding_factory.py", line 48, in create
return HuggingFaceEmbeddings(**new_kwargs)
File "/mnt/data/xiuzhu/DB-GPT/dbgpt/rag/embedding/embeddings.py", line 91, in init
self.client = sentence_transformers.SentenceTransformer(
File "/home/dtstack/miniconda3/envs/dbgpt_0.4.6/lib/python3.10/site-packages/sentence_transformers/SentenceTransformer.py", line 77, in init
raise ValueError("Path {} not found".format(model_name_or_path))
ValueError: Path /mnt/data/xiuzhu/models/text2vec-large-chinese not found

Close #1094

How Has This Been Tested?

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Checklist:

• My code follows the style guidelines of this project
• I have already rebased the commits and make the commit message conform to the project standard.
• I have performed a self-review of my own code
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• I have made corresponding changes to the documentation
• Any dependent changes have been merged and published in downstream modules

[xiuzhu9527]

issues: #1094

[xiuzhu9527]

@csunny Can you help review this PR? THX!

[csunny]

@xiuzhu9527 Thank you very much for your PR, LGTM

[Aries-ckt]

r+