### Godot version

any version after 74458b6

### System information

Linux x64, but likely irrelevant

### Issue description

OpenXR action maps are not properly exported in recent builds of Godot 4: the `.res` file is small and does no longer seem to contain anything of use. In-game, no actions are passed on to OpenXR (obviously).

I bisected the issue down to https://github.com/godotengine/godot/commit/74458b6e9bed0f28db3374c7406eacbcf4b09b9d, which was merged in #70377.

### Steps to reproduce

1. Delete any previous export files (`.godot/exported/*/*.pkg`)
2. Perform an export (I did one for Android, but it likely works with anything)
3. Observe OpenXR actions not working in the export (error spam 'sync_action_sets: Condition "active_sets.size() == 0"'), and the exported action map file being very small (`.godot/exported/*/*.pkg`, from a few tens of kilobytes down to 296 bytes)

### Minimal reproduction project

Any OpenXR project can be used, such as https://github.com/BastiaanOlij/godot4_openxr_demo
if (export_plugins[i]->extra_files[j].remap) {
						do_export = false; 
						path_remaps.push_back(path);
						path_remaps.push_back(export_plugins[i]->extra_files[j].path);
					}
				}
				if (export_plugins[i]->skipped) {
					do_export = false;
				}
				export_plugins.write[i]->_clear();
				if (!do_export) {
					break; 
				}
			}
			
			if (do_export) {
				
				bool force_binary = convert_text_to_binary && (path.get_extension().to_lower() == "tres" || path.get_extension().to_lower() == "tscn");
				String export_path = _export_customize(path, customize_resources_plugins, customize_scenes_plugins, export_cache, export_base_path, force_binary);
				if (export_path != path) {
					
					path_remaps.push_back(path);
					path_remaps.push_back(export_path);
				}
				Vector<uint8_t> array = FileAccess::get_file_as_bytes(export_path);
				err = p_func(p_udata, export_path, array, idx, total, enc_in_filters, enc_ex_filters, key);
				if (err != OK) {
					return err;
				}
			}