Update Safari data for ExtendableCookieChangeEvent API

[queengooborg]

This PR updates and corrects version values for Safari (Desktop and iOS/iPadOS) for the ExtendableCookieChangeEvent API. The mdn-bcd-collector reported this to be unsupported in Safari 18.4 through 18.6, even though it was reported as supported in Safari 18.4 beta. After doing some additional digging, it appears that this feature was hidden behind a flag that must have been enabled in 18.4 beta but disabled in stable releases.

[github-actions]

Tip: Review these changes grouped by change (recommended for most PRs), or grouped by feature (for large PRs).

[caugner]

Do we really need to repeat the flags on the subfeatures?

In #27726, I asked for these to be removed. If the interface is behind a flag, all the subfeatures are implicitly behind that flag as well, aren't they? Similarly, if a parent feature is only implemented with an alternative name, we don't specify the alternative name on the subfeatures (it would be misleading).

[queengooborg]

Yes, we should be propagating the flag data down to subfeatures.

Unlike prefixes or alternative names, flags apply directly to the subfeatures as well. By copying the data down to subfeatures, it allows consumers to understand that a flag must be enabled for the feature, even if they're looking at a small scope such as a single method or property.

Another benefit of copying the flag data down to subfeatures (and not in a build step) is that it makes it easier for tooling, such as the collector, to update this data once the flag's been enabled by default. In fact, it was actually due to the collector tests that the lack of default support was detected!

While the collector could be updated to account for parent flag data, based upon my understanding of the way the new update script works, that would involve a complete rewrite. Either that, or a whole list of results overrides would have to be maintained!