LibGUI: Make toolbar buttons non-focusable by default

Toolbar buttons are meant for quick mouse access to common actions,
while quick keyboard access is normally achieved via keyboard shortcuts
and underlined menu items.

This makes interfaces with many toolbar buttons (e.g GUI::FilePicker)
a lot nicer to navigate via keyboard.

Userland/Libraries/LibGUI/Toolbar.cpp

@@ -52,7 +52,7 @@ private:
             set_exclusive(true);
         set_action(action);
         set_tooltip(tooltip(action));
-        set_focus_policy(FocusPolicy::TabFocus);
+        set_focus_policy(FocusPolicy::NoFocus);
         if (action.icon())
             set_icon(action.icon());
         else