fix: use relative path for functions folder

[khendrikse]

Summary

When running netlify init to set up a new project (one that hasn't been configured in your Netlify account yet), the CLI was sending an absolute path for the functions directory to Netlify's API instead of a relative path.

If you initialized a project on your local machine at:

/Users/foo/Projects/Work/project-1/

The functions directory would be sent to Netlify as:

/Users/foo/Projects/Work/project-1/netlify/functions

Instead of the correct relative path:

netlify/functions

Root Cause

The issue was in src/utils/init/utils.ts where the config.build.functions value (which comes from @netlify/config package and is resolved to an absolute path) was being used directly without converting it to a relative path before sending it to the Netlify API. The fix ensures that any absolute paths are converted to paths relative to the repository root before being sent to the API, so they work correctly in any build environment.

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[github-actions]

📊 Benchmark results

Comparing with 9ae17b5

• Dependency count: 1,029 (no change)
• Package size: 284 MB (no change)
• Number of ts-expect-error directives: 379 (no change)