epiphany: clipboard/website-data permission prompt incorrectly grants camera and microphone access

A logic error in Epiphany's site permission handling can cause camera and microphone access to be granted when the user only approves a different permission.

In src/ephy-window.c, set_permission() stores the user's Allow/Deny choice after a WebKit permission dialog. Types CLIPBOARD and WEBSITE_DATA_ACCESS are not stored by ephy_permission_is_stored_by_permissions_manager(), so control fell into an else-if that was written as:

} else if (EPHY_PERMISSION_TYPE_ACCESS_WEBCAM_AND_MICROPHONE) {

Because that expression is a non-zero enum constant, the branch always ran for those types and wrote EPHY_PERMISSION_PERMIT for both ACCESS_WEBCAM and ACCESS_MICROPHONE for the site origin. The user only saw a Clipboard or Website Data Access dialog.

A malicious site that obtains approval for clipboard or third-party storage access can afterwards use getUserMedia without a further camera/microphone prompt, exposing audiovisual confidentiality.

Requirements: the victim must visit a malicious page and click Allow on a clipboard or website-data-access prompt.

Affected: Epiphany >= 45.0 (bug present at least through 51.x).
Fixed: https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/2249 (commit 480c3648).
Upstream: https://gitlab.gnome.org/GNOME/epiphany/-/work_items/2976
Reporter acknowledgment: Fernando Munoz