Cast records_per_page as int

Generates an error if a string (from the request) is passed into Illuminate\Database\Query\Builder::limit() with MongoDB driver.

src/Components/RecordsPerPage.php

@@ -73,7 +73,7 @@ public function getValue()
         if ($from_input === null) {
             return $this->grid->getConfig()->getPageSize();
         } else {
-            return $from_input;
+            return (int) $from_input;
         }
     }