Merge branch '6.0' into 6.1

* 6.0:
  [Mailer] fix tests
  [HttpFoundation] Prevent PHP Warning: Session ID is too long or contains illegal characters
  [Messenger] fix test
  [Messenger] Ceil waiting time when multiplier is a float on retry
  Spaces in system temp folder path cause deprecation errors in php 8

Author: nicolas-grekas

Loader/XmlFileLoader.php

@@ -683,7 +683,7 @@ private function shouldEnableEntityLoader(): bool
             });
             $schema = '<?xml version="1.0" encoding="utf-8"?>
 <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
-  <xsd:include schemaLocation="file:///'.str_replace('\\', '/', $tmpfile).'" />
+  <xsd:include schemaLocation="file:///'.rawurlencode(str_replace('\\', '/', $tmpfile)).'" />
 </xsd:schema>';
             file_put_contents($tmpfile, '<?xml version="1.0" encoding="utf-8"?>
 <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">