Allow browser contextmenu while holding shift

[Venefilyn]

Firefox already disallows pages from interrupting the browser contextmenu if you hold down shift while right-clicking.

Since it is a QoL thing for users to be able to access the browser contextmenu easily we should have an option that allows this no matter what. Making it consistent with Firefox means we are also consistent throughout all browsers.

For example, a user could use an extension that improves accessibility, want to translate something, or simply inspect the page. Without this change it is more difficult as they have to work around it and in some cases not be able to at all.