[bugfix] Fix issue when llm config is not defined

[deshraj]

Description

Recent integration of the CLIP model is breaking the package with AttributeError since the llm config is optional to pass in the CustomApp. This PR adds a check for the same to fix the issue.

Also, ran make format to prettify the code.

Type of change

• Bug fix (non-breaking change which fixes an issue)

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Files	Coverage Δ
embedchain/config/llm/base_llm_config.py	94.73% <ø> (ø)
embedchain/data_formatter/data_formatter.py	86.79% <100.00%> (ø)
embedchain/embedchain.py	73.89% <100.00%> (ø)
embedchain/llm/gpt4all.py	66.66% <ø> (ø)
embedchain/models/clip_processor.py	84.21% <100.00%> (ø)
embedchain/vectordb/chroma.py	82.79% <100.00%> (ø)
embedchain/vectordb/elasticsearch.py	67.53% <100.00%> (ø)
embedchain/loaders/images.py	30.00% <66.66%> (ø)

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