test: fix npm test compatibility with v27 nightly

[MikeMcC399]

• closes npm 12 - npm run tap (2 failures) #1130
• supersedes test: use npm_config_extra_param for npm custom install test (npm 12) #1132
• supersedes test: use npm_config_allow_git all to install from git source (npm 12) #1133

Situation

Running npm test fails under Node.js v27 nightlies, which now include npm@12.1.0.

Change

1. Add the environment variable npm_config_allow_git: 'all' to the test "citgm: omg-i-pass from git url" in test/test-citgm.js.

2. Replace the parameter --extra-param with the environment variable npm_config_extra_param instead of passing it using the CLI. See https://docs.npmjs.com/cli/v12/using-npm/config#environment-variables

Verification

On Ubuntu 26.04.1 LTS, with n Node.js version manager installed.

n nightly # for example nightly/27.0.0-nightly20261007aa1bf2cc37
git clone https://github.com/nodejs/citgm
cd citgm
npm install
npx tap test/test-citgm.js
npx tap test/npm/test-npm-install.js
npm test

Confirm successful test.

Checklist

• npm test passes
• contribution guidelines followed
  here

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.11%. Comparing base (17e7dea) to head (c9370b1).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1188      +/-   ##
==========================================
- Coverage   96.20%   96.11%   -0.10%     
==========================================
  Files          29       29              
  Lines        2213     2213              
==========================================
- Hits         2129     2127       -2     
- Misses         84       86       +2     

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