Add wxRibbonBar::GetPageById()

To find a page by ID currently you have to use a recursive FindWindow
(which would also look at the child Panel windows). This function allows
for finding a page by ID more elegantly.

Closes #24211.

interface/wx/ribbon/bar.h

@@ -303,6 +303,15 @@ public:
     */
     wxRibbonPage* GetPage(int n);
 
+    /**
+        Get a page by window ID.
+
+        @NULL will be returned if no page with the ID is found.
+
+        @since 3.3.0
+    */
+    wxRibbonPage* GetPageById(wxWindowID id);
+
     /**
         Get the number of pages in this bar.