Use checked handles for app dialogs

src/node_dialog_export_ppbr.cpp

@@ -3,7 +3,6 @@
 #include "node_dialog_export_ppbr.h"
 #include "app.h"
 #include "image.h"
-#include "legacy_ui_overlay_services.h"
 
 Node* NodeDialogExportPPBR::clone_instantiate() const
 {
@@ -31,7 +30,6 @@ void NodeDialogExportPPBR::init_controls()
         m_dest_path_txt->SetVisibility(false);
     btn_ok = find<NodeButton>("btn-ok");
     btn_cancel = find<NodeButton>("btn-cancel");
-    pp::panopainter::bind_legacy_click_destroys_node(*btn_cancel, *this);
     btn_header_open = find<NodeButton>("header-open");
     btn_header_open->on_click = [this] (Node*) {
         open_header();