### 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
err = p_func(p_udata, path + ".import", sarr, idx, total, enc_in_filters, enc_ex_filters, key);
				if (err != OK) {
					return err;
				}
				
				sarr = FileAccess::get_file_as_bytes(export_path);
				err = p_func(p_udata, export_path, sarr, idx, total, enc_in_filters, enc_ex_filters, key);
				if (err != OK) {
					return err;
				}
			} else {
				
				Ref<ConfigFile> config;
				config.instantiate();
				err = config->load(path + ".import");
				if (err != OK) {
					ERR_PRINT("Could not parse: '" + path + "', not exported.");
					continue;
				}
				String importer_type = config->get_value("remap", "importer");
				if (importer_type == "keep") {
					
					Vector<uint8_t> array = FileAccess::get_file_as_bytes(path);
					err = p_func(p_udata, path, array, idx, total, enc_in_filters, enc_ex_filters, key);
					if (err != OK) {
						return err;
					}
					continue;
				}
				List<String> remaps;