fix(ci): remove broken npm self-update step

Node 22 runners ship with a working npm. The npm install -g npm@latest
step breaks with 'Cannot find module promise-retry' due to a known
compatibility issue in npm's self-update path.

Author: mvanhorn

.github/workflows/publish.yml

@@ -20,7 +20,6 @@ jobs:
         with:
           node-version: 22
           registry-url: https://registry.npmjs.org
-      - run: npm install -g npm@latest
       - run: npm ci
       - run: npm run build
       - run: npm publish --provenance --access public