Replace proj/Units enum with typedef

src/ol/format/Feature.js

@@ -1,7 +1,6 @@
 /**
  * @module ol/format/Feature
  */
-import Units from '../proj/Units.js';
 import {abstract} from '../util.js';
 import {
   equivalent as equivalentProjection,
@@ -103,7 +102,7 @@ class FeatureFormat {
       if (
         opt_options.extent &&
         dataProjection &&
-        dataProjection.getUnits() === Units.TILE_PIXELS
+        dataProjection.getUnits() === 'tile-pixels'
       ) {
         dataProjection = getProjection(dataProjection);
         dataProjection.setWorldExtent(opt_options.extent);

src/ol/format/MVT.js

@@ -13,7 +13,6 @@ import Point from '../geom/Point.js';
 import Polygon from '../geom/Polygon.js';
 import Projection from '../proj/Projection.js';
 import RenderFeature from '../render/Feature.js';
-import Units from '../proj/Units.js';
 import {assert} from '../asserts.js';
 import {get} from '../proj.js';
 import {inflateEnds} from '../geom/flat/orient.js';
@@ -52,7 +51,7 @@ class MVT extends FeatureFormat {
      */
     this.dataProjection = new Projection({
       code: '',
-      units: Units.TILE_PIXELS,
+      units: 'tile-pixels',
     });
 
     /**