Disable voice routing. (#3475)

Fixes #3073
Fixes #2620

Author: bluemarvin

app/src/common/shared/org/mozilla/vrbrowser/browser/engine/SessionUtils.java

@@ -43,6 +43,7 @@ public static void vrPrefsWorkAround(Context aContext, Bundle aExtras) {
             out.write("user_pref(\"gfx.webrender.force-disabled\", true);\n".getBytes());
             // Disable web extension process until it is able to restart.
             out.write("user_pref(\"extensions.webextensions.remote\", false);\n".getBytes());
+            out.write("user_pref(\"media.cubeb.output_voice_routing\", false);\n)".getBytes());
             int msaa = SettingsStore.getInstance(aContext).getMSAALevel();
             if (msaa > 0) {
                 int msaaLevel = msaa == 2 ? 4 : 2;