modules: systemd_failed_units: Enforce visibility of event box on every update

Instead if guarding visibility in if condition, enforce visibility
regardless of the state of the current update.

Signed-off-by: Steffen Kothe <steffen.kothe@skothe.net>

src/modules/systemd_failed_units.cpp

@@ -109,9 +109,8 @@ auto SystemdFailedUnits::update() -> void {
     event_box_.set_visible(false);
     return;
   }
-  if (!event_box_.get_visible()) {
+
   event_box_.set_visible(true);
-  }
 
   // Set state class.
   if (!last_status.empty() && label_.get_style_context()->has_class(last_status)) {