### 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
Ref<Theme> theme = EditorNode::get_singleton()->get_editor_theme();
	ERR_FAIL_COND_V(theme.is_null(), Ref<ImageTexture>());
	if (EditorNode::get_singleton()->get_main_screen_control()->is_layout_rtl()) {
		return theme->get_icon(SNAME("PlayBackwards"), SNAME("EditorIcons"));
	} else {
		return theme->get_icon(SNAME("Play"), SNAME("EditorIcons"));
	}
}
String EditorExportPlatform::find_export_template(String template_file_name, String *err) const {