This PR does **one** thing:
it changes the events for potentially stale to:
- Only being emitted when potentially stale gets turned on
- In doing so, it also simplifies the event that's getting emitted,
removing the `data` property.
- The event is also renamed to better match the existing
`feature-stale-on` and `...-off` events.
The addon listening was broken out into a separate PR (#4279)
## Old description
This change lets all addons listen for events when features get marked
or unmarked as potentially stale.
### Discussion
#### All addons?
Should this be available to all addons? I can't see a reason why it
shouldn't be available to all addons, but I might be missing
something.
**Update**: spoke to a couple people. Can see no reason why this isn't
okay.
#### Should it be behind a flag?
The feature is still behind a flag, but the event type is not. Should
we gate the event being available until we actually emit the event?
That would require some more code, but could yield less potential
confusion.
Open to hearing your thoughts.
This PR activates the event emission that was prepared for in
https://github.com/Unleash/unleash/pull/4239.
It emits events (behind a flag) when something is marked as potentially
stale or the opposite.
It takes the features returned from the store and creates events out of
them.
The events only contain data, no preData. This is because the preData
can easily be inferred and because it gives a nicer event in the event
log.
Here is an image of the difference. The top event uses only data, so it
shows the name of the feature and the new potentiallyStale status. The
bottom event uses both preData and data, so it only shows the new
potentiallyStale status and not the feature name (unless you show the
raw event):
Should not be merged before #4239. Merge that and then rebase this off
main or cherry the commit.
## Discussion
### `preData`
Should we also use preData or is it enough to use only data? It seems
unnecessary in this event, but I'm open to hearing your thoughts.
### event author: `createdBy`
I've set `unleash-system` as the `createdBy` property on these events
because they are generated by the system. I found the same string used
some other places. However, it may be that there we want to use a
different author.
