fix: correct exception handling in PHP wrapper (#3901)

The `catch` is hinting on `\Exception` [1] which has not `getName`-method.
To identify the type of exception, `get_class` can be used.

[1] https://www.php.net/manual/de/class.exception.php

Co-authored-by: HugoCasa <hugo@casademont.ch>

backend/windmill-worker/src/php_executor.rs

@@ -229,7 +229,7 @@ try {{
 }} catch (Exception $e) {{
     $err = [
         "message" => $e->getMessage(),
-        "name" => $e->getName(),
+        "name" => get_class($e),
         "stack" => $e->getTraceAsString()
     ];
     $step_id = getenv('WM_FLOW_STEP_ID');