### 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_FAIL_COND_V_MSG(p_total < 1, ERR_PARAMETER_RANGE_ERROR, "Must select at least one file to export.");
	PackData *pd = (PackData *)p_userdata;
	SavedData sd;
	sd.path_utf8 = p_path.utf8();
	sd.ofs = pd->f->get_position();
	sd.size = p_data.size();
	sd.encrypted = false;
	for (int i = 0; i < p_enc_in_filters.size(); ++i) {
		if (p_path.matchn(p_enc_in_filters[i]) || p_path.replace("res://", "").matchn(p_enc_in_filters[i])) {
			sd.encrypted = true;
			break;
		}
	}
	for (int i = 0; i < p_enc_ex_filters.size(); ++i) {
		if (p_path.matchn(p_enc_ex_filters[i]) || p_path.replace("res://", "").matchn(p_enc_ex_filters[i])) {
			sd.encrypted = false;
			break;
		}
	}
	Ref<FileAccessEncrypted> fae;
	Ref<FileAccess> ftmp = pd->f;
	if (sd.encrypted) {
		fae.instantiate();
		ERR_FAIL_COND_V(fae.is_null(), ERR_SKIP);