This exposes all possible values, but before
https://codereview.qt-project.org/#/c/240121/ we won't be able to change those
at runtime (or enable URL patterns, which thankfully weren't enabled for the
old setting).
In theory, it'd be possible to handle the "public-interface-only" value via
QWebEngineSettings without requiring a restart, but it isn't worth the trouble.
Closes#4201