Fix PHP 8.4 implicit nullable parameter deprecations in Predis library

PHP 8.4 deprecates implicitly nullable parameter types. Parameters with a default value of `null` must now be explicitly marked as nullable (e.g., `?Type $var = null`).

This change updates the vendored `Predis` library in `plugins/cache-redis/` to comply with this requirement. It scans for function signatures like `Type $var = null` and updates them to `?Type $var = null`. This ensures compatibility with PHP 8.4 and PHP 8.5 while maintaining backward compatibility.

Affected files include `Predis` interfaces, connection classes, and command definitions.
Also updated PHPDoc `@method` annotations to reflect nullable types.

plugins/cache-redis/Predis/CommunicationException.php

@@ -32,7 +32,7 @@ abstract class CommunicationException extends PredisException
         NodeConnectionInterface $connection,
         $message = '',
         $code = 0,
-        Exception $innerException = null
+        ?Exception $innerException = null
     ) {
         parent::__construct(
             is_null($message) ? '' : $message,