[gnome-panel] launcher: use correct filename when editing custom launcher

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 53a133bd627d6b6a9b67e1787a95822a8d9be854
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Thu May 26 23:06:03 2022 +0300

    launcher: use correct filename when editing custom launcher
    
    https://bugs.launchpad.net/ubuntu/+source/gnome-panel/+bug/1975822

 modules/launcher/gp-launcher-properties.c | 9 +++++++++
 1 file changed, 9 insertions(+)
---
diff --git a/modules/launcher/gp-launcher-properties.c b/modules/launcher/gp-launcher-properties.c
index fbf08cf53..fa8845a62 100644
--- a/modules/launcher/gp-launcher-properties.c
+++ b/modules/launcher/gp-launcher-properties.c
@@ -94,6 +94,15 @@ get_launcher_filename (GpLauncherProperties  *self,
 
       return TRUE;
     }
+  else if (!g_path_is_absolute (location))
+    {
+      *filename = g_build_filename (launchers_dir, location, NULL);
+
+      g_free (location);
+      g_free (launchers_dir);
+
+      return FALSE;
+    }
 
   *filename = location;