Fix installing export templates from file

3de20641f5690aba7551da5c592a79d44af54fef did break installing export
templates from file. This patch is fixing it.

editor/export_template_manager.cpp

@@ -555,7 +555,7 @@ ExportTemplateManager::ExportTemplateManager() {
 	template_open->add_filter("*.tpz ; Godot Export Templates");
 	template_open->set_access(FileDialog::ACCESS_FILESYSTEM);
 	template_open->set_mode(FileDialog::MODE_OPEN_FILE);
-	template_open->connect("file_selected", this, "_install_from_file");
+	template_open->connect("file_selected", this, "_install_from_file", varray(true));
 	add_child(template_open);
 
 	set_title(TTR("Export Template Manager"));