Package viewer page breaks if package doesn't have a main export

[jaydenseric]

The registry package viewer page breaks if the package has optimal module design and only has individual deep exports, and no main export. For example, at https://yarnpkg.com/package?name=graphql-react the error is:

Missing "." specifier in "graphql-react" package

[smeng9]

Same issue for @babel/runtime https://yarnpkg.com/package?q=babel&name=%40babel%2Fruntime