Layouts: Fix styling of "preferences"- and "BackSpace"-buttons

Part-of: <https://gitlab.gnome.org/World/Phosh/squeekboard/-/merge_requests/643>

data/keyboards/it_wide.yaml

@@ -8,7 +8,7 @@ outlines:
     change-view:   { width: 77.52, height: 42 }
     change-view-2:      { width: 91.26, height: 42 }
     spaceline: { width: 146.7, height: 42 }
-    special:   { width: 64.76, height: 42 }
+    special:   { width: 52, height: 42 }
 
 views:
     base:
@@ -51,7 +51,7 @@ buttons:
         action: "erase"
     preferences:
         action: "show_prefs"
-        outline: "default"
+        outline: "special"
         icon: "keyboard-mode-symbolic"
     show_numbers:
         action: