In older versions of `bazelbuild/rules_nodejs`, the `npm_package.pack`
rule does not work on Windows. This has been fixed in
bazelbuild/rules_nodejs#2257, but the fix is not available before
[version 2.3.0][1].
Currently, we use version 2.2.0 (see [WORKSPACE][2]). In order to allow
the `zone-js-builder.js` script to work on Windows, this commit switches
to using `npm pack` directly, intead of relying on `npm_package.pack`.
For reference, the version of `bazelbuild/rules_nodejs` was updated to
2.3.2 in PR #39636, but this was later reverted due to CI flakes
(4e6d69cc85).
[1]: https://github.com/bazelbuild/rules_nodejs/releases/tag/2.3.0
[2]: fc64fa8e1a/WORKSPACE (L12)
PR Close#40557