[4.x] Update child URIs when parent slug changes

[jacksleight]

Fixes https://github.com/statamic/cms/issues/9445

This PR implements a new listener that updates the URI index for all child pages whenever the parent page is updated.

It should probably only run if the slug has actually changed, but I'm not sure if there's a way to check that in an EntrySaved listener?

I couldn't figure out the right way or place to do the test, if you can point me in the right direction I'll add that in.

[jacksleight]

Oh yeah good point. I only did it like that because I was copying the other UpdateStructuredEntryUris listener that runs for tree updates, but saveQuietly is definitely an issue.

Shall I change it?

[jasonvarga]

I think its okay where it is 👌

It should probably only run if the slug has actually changed, but I'm not sure if there's a way to check that in an EntrySaved listener?

There's no way at the moment, but should be once #5502 gets implemented.

[jasonvarga]

Since #5502 is pretty close to being merged, I'll mark this as a draft until we implement only doing this when the slug changes.

[jacksleight]

Cool, will do.

[jacksleight]

Once the isDirty PR is ready, use it to make sure that all of this only happens if the slug has changed.

Done

[jasonvarga]

Duncan was right. Not sure why I was okay with leaving it as an event. Anyway, I updated it for you.

Thanks both!