[BUG] npm invalid config warning duplicates lock file version

[broksonic21]

Is there an existing issue for this?

• I have searched the existing issues

This issue exists in the latest npm version

• I am using the latest npm

Current Behavior

If you have lockfile-version=5 by mistake (or anything other than missing, 1, 2 or 3) in the .npmrc, npm warnings/errors show a non-uniq list of error cases - null, 1, 2, 3, 1, 2, 3

npm WARN invalid config lockfile-version="5" set in /Users/REDACTED/REDACTED/REDACTED-website/.npmrc
npm WARN invalid config Must be one of: null, 1, 2, 3, 1, 2, 3
npm ERR! Invalid lockfileVersion config: 5

Expected Behavior

Should uniq, and return just null, 1, 2, 3

npm WARN invalid config lockfile-version="5" set in /Users/REDACTED/REDACTED/REDACTED-website/.npmrc
npm WARN invalid config Must be one of: null, 1, 2, 3
npm ERR! Invalid lockfileVersion config: 5

Steps To Reproduce

With npm 9.6.5

have a package.json and an .npmrc
in the .npmrc, have this

lockfile-version=5

run npm install

Get the warning

Environment

• npm: 9.6.5
• Node.js: v18.16.0
• OS Name: Mac

[kashyapkaki]

Hi @wraithgar, have raised PR for the above issue.