Docs: remove Safety notes from functions which are not unsafe; mark get_module_*_conf unsafe

[pchickey]

Proposed changes

This PR removes # Safety sections from the rustdocs of functions which are not unsafe. I noticed this when reading one of the docs and scanned through the entire repo's use of # Safety docs to collect this set.

The Request::get_module_*_conf functions had Safety notes describing their invariants but were not unsafe, despite definitely being unsafe, so I changed those function signatures instead of removing the docs.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have written my commit messages in the Conventional Commits format.
• I have read the CONTRIBUTING doc
• I have added tests (when possible) that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto master
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

[bavshin-f5]

Can you please reorganize the changes into 2 commits: Request method changes and safety notes removal.
Otherwise looks good.