import textDirection instead of caching first time rtl detection

modules/svg/labels.js

@@ -1,6 +1,7 @@
 import * as d3 from 'd3';
 import _ from 'lodash';
 import rbush from 'rbush';
+import { textDirection } from '../util/locale';
 
 import {
     geoExtent,
@@ -355,7 +356,6 @@ export function svgLabels(projection, context) {
 
             var coord = projection(entity.loc),
                 margin = 2,
-                textDirection = detected.textDirection,
                 offset = pointOffsets[textDirection],
                 p = {
                     height: height,