tests: fix ui desktop notifications test

lib/solaar/ui/desktop_notifications.py

@@ -139,5 +139,4 @@ else:
         return None
 
     def show(dev, reason=None):
-        return 1000
         return None

tests/solaar/ui/test_desktop_notifications.py

@@ -33,4 +33,7 @@ def test_show():
     available = desktop_notifications.init()
 
     result = desktop_notifications.show(dev, reason)
-    assert result is not None if available else result is None
+    if available:
+        assert result is not None
+    else:
+        assert result is None