In order to retrieve the ngcc configuration (if any) for an entry-point,
ngcc has to detect the containing package's version.
Previously, ngcc would try to read the version from the entry-point's
`package.json` file, which was different than the package's top-level
`package.json` for secondary entry-points. For example, it would try to
read it from `node_modules/@angular/common/http/package.json` for
entry-point `@angular/common/http`. However, the `package.json` files
for secondary entry-points are not guaranteed to include a `version`
property.
This commit fixes this by first trying to read the version from the
_package's_ `package.json` (falling back to the entry-point's
`package.json`). For example, it will first try to read it from
`@angular/common/package.json` for entry-point `@angular/common/http`.
PR Close#37040
829ddf95e5