API Remove unnecessary getGenerator() method.

`getIterator()` now returns a generator by default.

src/Forms/GridField/GridFieldExportButton.php

@@ -223,10 +223,6 @@ public function generateExportFileData($gridField)
 
         // Remove limit as the list may be paginated, we want the full list for the export
         $items = $items->limit(null);
-        // Use Generator in applicable cases to reduce memory consumption
-        $items = $items instanceof DataList
-            ? $items->getGenerator()
-            : $items;
 
         /** @var DataObject $item */
         foreach ($items as $item) {

src/ORM/DataList.php

@@ -791,20 +791,6 @@ public function each($callback)
         return $this;
     }
 
-    /**
-     * Returns a generator for this DataList
-     *
-     * @return \Generator&DataObject[]
-     */
-    public function getGenerator()
-    {
-        $query = $this->dataQuery->query()->execute();
-
-        while ($row = $query->record()) {
-            yield $this->createDataObject($row);
-        }
-    }
-
     public function debug()
     {
         $val = "<h2>" . static::class . "</h2><ul>";
@@ -1206,7 +1192,7 @@ public function shuffle()
      */
     public function removeAll()
     {
-        foreach ($this->getGenerator() as $item) {
+        foreach ($this as $item) {
             $this->remove($item);
         }
         return $this;