Figure out why some tests need application-template-wrapper enabled to pass

As part of my work to upgrade ember-cli-fastboot using ember-cli-update I noticed that some tests failed because they needed the application-template-wrapper to be enabled in optitonal-features.

I didn't really have the time to investigate why, and I didn't want to block the other PR any more than it already was 🙈 so this issue is to keep track that it needs to be looked into.

To test this, just undo the work in this commit and see why some tests fail 🤷 I have a feeling it could just be a selector depending on the wrapper div existing 🤔