docs: fix typos in brain_defaults.py, llm_endpoint.py and utils.py

[yumosx]

Description

brain_default.py: defaultone ---> default one
llm_endpoints.py: acces ---> access
utils.py: mesages ---> messages

Checklist before requesting a review

Please delete options that are not relevant.

• [v] My code follows the style guidelines of this project
• [v] I have performed a self-review of my code
• [-] I have commented hard-to-understand areas
• [-] I have ideally added tests that prove my fix is effective or that my feature works
• [-] New and existing unit tests pass locally with my changes
• [-] Any dependent changes have been merged

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