Expose bug in Query { isLoggedin }

The idMiddleware was adding selection fields to the resolveInfo even if
the selection fields were empty. This caused a bug for each resolve
function including

```
{
 isLoggedin
}
```

which does not have any additional curly braces after the query.

src/graphql-schema.spec.js

@@ -16,6 +16,15 @@ afterEach(async () => {
   await factory.cleanDatabase()
 })
 
+describe('isLoggedIn', () => {
+  describe('unauthenticated', () => {
+    it('returns false', async () => {
+      const query = '{ isLoggedIn }'
+      await expect(request(host, query)).resolves.toEqual({ isLoggedIn: false })
+    })
+  })
+})
+
 describe('login', () => {
   const mutation = (params) => {
     const { email, password } = params