Configure npm to prefer online installation

Instead of using a local cache, so that mirror
checks apply.

Bug: none
Change-Id: Ifa87fcbcb6491f05194417dc586b32ed9099b928
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/5478387
Reviewed-by: Simon Zünd <[email protected]>
Commit-Queue: Alex Rudenko <[email protected]>

Author: OrKoN

.npmrc

@@ -5,5 +5,6 @@ omit = optional  # This is to avoid downloading esbuild-* package.
 ignore-scripts = true
 save-exact = true
 save-dev = true # Only devDependencies are allowed.
+prefer-online = true # To consult the mirror instead of local cache.
 # See go/sk-npm-audit-mirror.
 registry = https://npm.skia.org/chrome-devtools