Fix PHPUnit failures after Symfony/Twig/PHPUnit API changes

[azine]

Motivation

• Make the bundle and its tests compatible with newer Symfony/Twig/PHPUnit APIs and harden runtime behavior for edge cases.
• Fix configuration definition issues that caused Symfony config tree validation failures when defaults and required flags conflicted.

Description

• Remove erroneous isRequired() flags from azine_email.no_reply child nodes to avoid "cannot be required and have a default value" errors (changes in DependencyInjection/Configuration.php).
• Replace legacy Twig filter and template APIs with modern equivalents by switching \Twig_SimpleFilter to \Twig\TwigFilter and using load() instead of loadTemplate() (changes in Services/AzineEmailTwigExtension.php and Services/AzineTwigSwiftMailer.php).
• Harden AzineEmailTemplateController by validating image file existence before creating BinaryFileResponse, making spam-check parsing robust for empty/invalid JSON responses, and using $request->get('emailSource') to avoid accessing an uninitialized typed Request bag (changes in Controller/AzineEmailTemplateController.php).
• Update PHPUnit tests for current PHPUnit/Twig behavior: use assertNotContains for array membership, update legacy Twig class references in tests, remove obsolete PHPUnit mock-object concrete typehint, change twig mock expectation from loadTemplate to load, and use createMock() for TokenStorageInterface in controller tests (changes under Tests/).

Testing

• Attempted to run composer install but it failed due to a PHP runtime mismatch: project requires php:^8.5 while the environment provides php 8.4.22-dev, so dependencies could not be installed and PHPUnit could not be executed.
• Because vendor dependencies were unavailable, vendor/bin/phpunit -c phpunit.xml.dist could not be run in this environment and automated test execution was not completed.
• The modifications are focused on API compatibility and defensive checks; they should be verified by running composer install on a PHP >= 8.5 environment and then executing vendor/bin/phpunit -c phpunit.xml.dist.

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Codex Task