Linux: Handle export preset compat with 'Linux/X11' platform name

Fixes #89012.

editor/export/editor_export.cpp

@@ -219,6 +219,12 @@ void EditorExport::load_config() {
 		}
 
 		String platform = config->get_value(section, "platform");
+#ifndef DISABLE_DEPRECATED
+		// Compatibility with Linux platform before 4.3.
+		if (platform == "Linux/X11") {
+			platform = "Linux";
+		}
+#endif
 
 		Ref<EditorExportPreset> preset;