Fix use of Ember global, breaking Ember 4

[simonihmig]

I think it's not ideal to rely on assumptions about the global require() and AMD-style modules, especially in a brave new Embroider world. But after all this is what the RFC706 suggests in the drawbacks section, and should be good enough to fix this for the short term...

Fixes #827

[simonihmig]

Somehow, the first attempt (first commit) of using just require('ember').default didn't work in Ember 3.26 (CI was failing), as that threw an error that the module is not defined (require.entries was an empty object), but it did work for 3.27 and 4.0 (tested locally)! 🤔

The fallback check in the 2nd commit fixes this. But given we don't test across Ember versions in CI yet, the confidence in this change is somewhat lower than I would want. Maybe we have to wait for #848 first?

[snewcomer]

👍 💯. This will fix it!

[snewcomer]

@simonihmig Still investigating but seeing ReferenceError: Ember is not defined at when adding your work to this PR.

https://github.com/ember-fastboot/ember-cli-fastboot/pull/848/checks?check_run_id=3400612883

https://github.com/ember-fastboot/ember-cli-fastboot/pull/848/files#diff-6332b424009db608242427547830fa767850f2b49ae9943dc54c8d43ba0e349bR4