[libadwaita] view-stack: Don't show duplicate name warnings for null names

[Alexander Mikhaylenko <alexm src gnome org>]

commit bf2e8620c24b08ace31d865fe7f0983c801e20fa
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Tue Jul 20 00:44:18 2021 +0500

    view-stack: Don't show duplicate name warnings for null names
    
    Having multiple pages with the null name isn't a problem to warn about.

 src/adw-view-stack.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/src/adw-view-stack.c b/src/adw-view-stack.c
index 2cf82ef6..1d269548 100644
--- a/src/adw-view-stack.c
+++ b/src/adw-view-stack.c
@@ -1587,7 +1587,8 @@ adw_view_stack_page_set_name (AdwViewStackPage *self,
 
   if (self->widget &&
       gtk_widget_get_parent (self->widget) &&
-      ADW_IS_VIEW_STACK (gtk_widget_get_parent (self->widget))) {
+      ADW_IS_VIEW_STACK (gtk_widget_get_parent (self->widget)) &&
+      name) {
     GList *l;
 
     stack = ADW_VIEW_STACK (gtk_widget_get_parent (self->widget));