Log Message:
xfce4-panel: update to 4.18.6

4.18.6 (2024-02-29)
======
- Update copyright year
- Do not use g_log_set_always_fatal()
- launcher: Ensure default icon in empty launchers
- build: Search for bind_textdomain_codeset in libintl too
- Fix memory management of GTypeModules
- pager: Avoid recursion in WnckScren signal handler
- pager: Do not query workspace count if screen is not initialized
- libxfce4panel: Fix custom menu items management
- clock: Create monitor proxy asynchronously
- Add missing G_BEGIN_DECLS
- Translation Updates:
  Czech, Finnish, Hungarian, Icelandic, Interlingue, Italian,
  Portuguese (Brazil), Turkish