[gnome-boxes] preferences, devices: Don't query for usbredir in Flatpak

[Felipe Borges <felipeborges src gnome org>]

commit a11b59f80ba4e52a1309ca680e874b0598206e13
Author: Felipe Borges <felipeborges gnome org>
Date:   Mon Jan 10 10:19:00 2022 +0100

    preferences, devices: Don't query for usbredir in Flatpak
    
    It isn't supported as of now.

 src/preferences/devices-page.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/preferences/devices-page.vala b/src/preferences/devices-page.vala
index 12395213..6c3df159 100644
--- a/src/preferences/devices-page.vala
+++ b/src/preferences/devices-page.vala
@@ -44,7 +44,7 @@ private void setup_usb_devices_list () {
             return;
         }
 
-        if (!(machine.display is SpiceDisplay))
+        if (!(machine.display is SpiceDisplay) || App.is_running_in_flatpak ())
             return;
 
         var spice_display = machine.display as SpiceDisplay;