Disable 5k youtube videos (#3288)

Work around for #3193

Author: bluemarvin

app/src/main/assets/web_extensions/webcompat_youtube/main.js

@@ -173,7 +173,10 @@ class YoutubeExtension {
 
     // Get's the preferred video qualities for the current device.
     getPreferredQualities() {
-        let all = ['hd2880', 'hd2160','hd1440', 'hd1080', 'hd720', 'large', 'medium'];
+        // Disable 5k video until issue can be resolved in Gecko Media Process
+        // see https://github.com/MozillaReality/FirefoxReality/issues/3193
+        // let all = ['hd2880', 'hd2160','hd1440', 'hd1080', 'hd720', 'large', 'medium'];
+        let all = ['hd2160','hd1440', 'hd1080', 'hd720', 'large', 'medium'];
         return all;
     }