Add test for Arr::reject method (#54863)

This commit adds test coverage for the Arr::reject method which filters
an array using the negation of a given callback. The test verifies:

- Basic rejection behavior with sequential arrays
- Key preservation with associative arrays

Author: mohammadrasoulasghari

Diff for: tests/Support/SupportArrTest.php

@@ -1533,4 +1533,32 @@ public function testSelect()
             [],
         ], Arr::select($array, null));
     }
+
+    public function testReject()
+    {
+        $array = [1, 2, 3, 4, 5, 6];
+
+        // Test rejection behavior (removing even numbers)
+        $result = Arr::reject($array, function ($value) {
+            return $value % 2 === 0;
+        });
+
+        $this->assertEquals([
+            0 => 1,
+            2 => 3,
+            4 => 5,
+        ], $result);
+
+        // Test key preservation with associative array
+        $assocArray = ['a' => 1, 'b' => 2, 'c' => 3, 'd' => 4];
+
+        $result = Arr::reject($assocArray, function ($value) {
+            return $value > 2;
+        });
+
+        $this->assertEquals([
+            'a' => 1,
+            'b' => 2,
+        ], $result);
+    }
 }