Initialize profiler property to null in Statement class

In PHP, ?-> still reads the property first; an uninitialized typed property throws before it can evaluate as null.

Signed-off-by: Mathias Berchtold <mberchtold@gmail.com>

Author: matbech

src/Statement.php

@@ -27,7 +27,7 @@ final class Statement implements StatementInterface, DriverAwareInterface, Profi
 
     protected Driver $driver;
 
-    protected ?ProfilerInterface $profiler;
+    protected ?ProfilerInterface $profiler = null;
 
     protected string $sql = '';