refs: https://github.com/TryGhost/Toolbox/issues/595
We're rolling out new rules around the node assert library, the first of which is enforcing the use of assert/strict. This means we don't need to use the strict version of methods, as the standard version will work that way by default.
This caught some gotchas in our existing usage of assert where the lack of strict mode had unexpected results:
- Url matching needs to be done on `url.href` see aa58b354a4
- Null and undefined are not the same thing, there were a few cases of this being confused
- Particularly questionable changes in [PostExporter tests](c1a468744b) tracked [here](https://github.com/TryGhost/Team/issues/3505).
- A typo see eaac9c293a
Moving forward, using assert strict should help us to catch unexpected behaviour, particularly around nulls and undefineds during implementation.
fixes https://github.com/TryGhost/Team/issues/2332
Saves events in the database and collects error information.
Do note that we can emit the same events multiple times, and as a result
out of order. That means we should correctly handle that a delivered
event might be fired after a permanent failure. So a delivered event is
ignored if the email is already marked as failed. Also delivered_at is
reset to null when we receive a permanent failure.
