Revert "Merge pull request #15312 from JuanitoFatas/action_view/asset_path"

This reverts commit 21ec7fefea5a1b823cb88733b019b3d52240801d.

Per #16911, there's actually a good reason for a "blank" value to have a
useful `to_s` here. So let's also add some tests to prove that.