After bringing the implementation of Navigator.plugins inline with the modern specs, we can get rid of some old code used to distinguish between web-visible and other plugins. We don't have such things anymore, so this code can be removed.
<rdar://problem/100643178>
Pull request: https://github.com/WebKit/WebKit/pull/4892
Committed 255101@main (af20d024151b): <https://commits.webkit.org/255101@main> Reviewed commits have been landed. Closing PR #4892 and removing active labels.