QtWebView WebRTC fails on macOS 10.14

I use QtWebView in Qt 6.4.2 to load a WebRTC client that needs access to the camera device.

This works fine on macOS 11, 12 and 13, but on 10.14 the Camera permission request is not relayed to the OS, so the WebRTC session fails

Note: Qt6 is officially supported on macOS back to version 10.14 (see docs). macOS users are particularly prone to sticking on old OS versions (like macOS 10.14 Mojave), especially if they are creator/producer types who rely on old OS versions to run their current setup of audio software. (It's incredibly frustrating for us developers, yes, but that's the reality of things.)

PROBLEM
QtWebView on macOS 10.14 does NOT successfully request the Camera permission that allows WebRTC functionality (eg video chat using webcam)

REPRODUCTION
I created a minimal test project to demonstrate this:
https://github.com/danryu/webview_camera_test
(It simply loads a QML WebView with a WebRTC demo url.)
Please try running the project on macOS 10.14 versus 11+.
(NOTE: you may need to add QT_WEBVIEW_PLUGIN=native to the Run environment in order to pick up the WebView plugin.)

Test Summary:

• macOS 11 and later: WebView requests Camera permission, WebRTC demo successful
  => SUCCESS
• macOS 10.14: WebView does NOT ask for Camera permission, WebRTC demo FAILS
  => FAILURE