Set commit and snippet notes feature category

What does this MR do and why?

Moves commit and snippet notes endpoints to the correct feature category

This is similar to !122543 (merged) but for commits and project snippets. I missed this earlier because I thought this was only used for issues and merge requests.

How to set up and validate locally

Open a commit / project snippet and check the logs with something like:

tail -f log/development_json.log | jq 'select(."meta.caller_id" == "Projects::NotesController#index") | { path: .path, status: .status, feature_category: ."meta.feature_category" }'

You will see the requests will now have the correct source_code_management feature category

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.