CSPViolationReportBody reporting false in Safari 18.4

[queengooborg]

In mdn/browser-compat-data#26533, it was reported that Safari 18.4 supports the CSPViolationReportBody API. However, the collector reports that it isn't supported.

The test depends on the ReportingObserver API, and the WPT test results says that "Report is observable to ReportingObserver" isn't supported. So, we need to figure out some other way to test support in Safari.

[gsnedders]

"CSPViolationReportBody" in window is true, so we can easily see that the prototype exists, even if we can't get an instance.

Though this of course falls into "what does it mean to support something", but https://bugs.webkit.org/show_bug.cgi?id=294048 I've filed for the underlying issue there…