Preload association inside Embedded Schema from Schema level

This PR suggests it should definitely be possible to preload test_assoc on a single TestEmbedded struct:

https://github.com/elixir-ecto/ecto/pull/3368

In the case you’re looking for in load_test, I’d expect this might work:

%Test{}
|> Repo.all()
|> Repo.preload(test_embedded: :test_assoc)

In the same way you’d preload a has_one and an association on that record.