Simplify vector tile projection handling

src/ol/format/Feature.js

@@ -111,14 +111,6 @@ class FeatureFormat {
     }, options);
   }
 
-  /**
-   * Get the extent from the source of the last {@link readFeatures} call.
-   * @return {import("../extent.js").Extent} Tile extent.
-   */
-  getLastExtent() {
-    return null;
-  }
-
   /**
    * @abstract
    * @return {import("./FormatType.js").default} Format.