[xdg-desktop-portal-gnome] ScreenCast: double-check the dialog handle exists before closing it

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit a60f4a2699936b5b86c9fe87c0fe5911af34a0af
Author: Jan Grulich <jgrulich redhat com>
Date:   Tue Jun 14 16:36:33 2022 +0200

    ScreenCast: double-check the dialog handle exists before closing it

 src/screencast.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/src/screencast.c b/src/screencast.c
index 7bf516e..e983a4d 100644
--- a/src/screencast.c
+++ b/src/screencast.c
@@ -869,7 +869,8 @@ screen_cast_session_close (Session *session)
       g_clear_object (&screen_cast_session->gnome_screen_cast_session);
     }
 
-  screen_cast_dialog_handle_close (screen_cast_session->dialog_handle);
+  g_clear_pointer (&screen_cast_session->dialog_handle,
+                   screen_cast_dialog_handle_close);
 }
 
 static void