Add WKNavigation SPI to check if the navigation had a user interaction. Also make sure that the value is correct for same-document navigations.
<rdar://96231513>
Pull request: https://github.com/WebKit/WebKit/pull/1961
Committed 252020@main (e5037a0c9f52): <https://commits.webkit.org/252020@main> Reviewed commits have been landed. Closing PR #1961 and removing active labels.