Allow to pass limit as null to not break the pipeline

src/core/etl/src/Flow/ETL/DataFrame.php

@@ -540,8 +540,12 @@ public function joinEach(DataFrameFactory $factory, Expression $on, string|Join
      *
      * @throws InvalidArgumentException
      */
-    public function limit(int $limit) : self
+    public function limit(?int $limit) : self
     {
+        if ($limit === null) {
+            return $this;
+        }
+
         $this->pipeline = $this->context->config->optimizer()->optimize(new LimitTransformer($limit), $this->pipeline);
 
         return $this;

src/core/etl/src/Flow/ETL/Transformation/Limit.php

@@ -8,7 +8,7 @@
 
 final readonly class Limit implements Transformation
 {
-    public function __construct(private int $limit)
+    public function __construct(private ?int $limit)
     {
     }
 

src/core/etl/tests/Flow/ETL/Tests/Integration/DataFrame/LimitTest.php

@@ -115,6 +115,21 @@ public function test_limit_below_0() : void
         df()->read(from_rows(\Flow\ETL\DSL\rows()))->limit(-1);
     }
 
+    public function test_limit_null() : void
+    {
+        $rows = df()
+            ->read(from_array(
+                \array_map(
+                    fn (int $id) : array => ['id' => $id],
+                    \range(1, 10)
+                )
+            ))
+            ->limit(null)
+            ->fetch();
+
+        self::assertCount(10, $rows);
+    }
+
     public function test_limit_when_transformation_is_expanding_rows_extracted_from_extractor() : void
     {
         $rows = df()