`extensions` should not ignore subpath imports when `ignorePackages` is used

[IanVS]

I have decided to add extensions to my typescript module imports, and import-x/extensions has been a godsend for the migration. However, one thing I've noticed is that when using the ignorePackages option, subpath imports like #api/... are treated as packages. I think you should be able to look for an import specifier starting with # (required by the node spec) and treat it as a subpath import, not a package.