bug symfony#60373 [FrameworkBundle] Ensure Email class exists before using it (Kocal)

This PR was merged into the 6.4 branch.

Discussion
----------

[FrameworkBundle] Ensure `Email` class exists before using it

| Q             | A
| ------------- | ---
| Branch?       | 6.4
| Bug fix?      | yes
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Issues        | Fix #... <!-- prefix each issue number with "Fix #", no need to create an issue if none exists, explain below instead -->
| License       | MIT

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I think the [dev-tests suite from Symfony UX](https://github.com/symfony/ux/actions/runs/14886649078/job/41808040295?pr=2711) broke after symfony#60365, see:
```
1) Symfony\UX\Icons\Tests\Integration\Command\ImportIconCommandTest::testCanImportIcon
Error: Class "Symfony\Component\Validator\Constraints\Email" not found

/home/runner/work/ux/ux/src/Icons/vendor/symfony/framework-bundle/DependencyInjection/Configuration.php:10[79](https://github.com/symfony/ux/actions/runs/14886649078/job/41808040295?pr=2711#step:8:80)
/home/runner/work/ux/ux/src/Icons/vendor/symfony/framework-bundle/DependencyInjection/Configuration.php:163
/home/runner/work/ux/ux/src/Icons/vendor/symfony/config/Definition/Processor.php:46
/home/runner/work/ux/ux/src/Icons/vendor/symfony/dependency-injection/Extension/Extension.php:109
/home/runner/work/ux/ux/src/Icons/vendor/symfony/framework-bundle/DependencyInjection/FrameworkExtension.php:306
/home/runner/work/ux/ux/src/Icons/vendor/symfony/dependency-injection/Compiler/MergeExtensionConfigurationPass.php:[81](https://github.com/symfony/ux/actions/runs/14886649078/job/41808040295?pr=2711#step:8:82)
/home/runner/work/ux/ux/src/Icons/vendor/symfony/http-kernel/DependencyInjection/MergeExtensionConfigurationPass.php:40
/home/runner/work/ux/ux/src/Icons/vendor/symfony/dependency-injection/Compiler/Compiler.php:73
/home/runner/work/ux/ux/src/Icons/vendor/symfony/dependency-injection/ContainerBuilder.php:813
/home/runner/work/ux/ux/src/Icons/vendor/symfony/http-kernel/Kernel.php:499
/home/runner/work/ux/ux/src/Icons/vendor/symfony/http-kernel/Kernel.php:744
/home/runner/work/ux/ux/src/Icons/vendor/symfony/http-kernel/Kernel.php:120
/home/runner/work/ux/ux/src/Icons/vendor/symfony/framework-bundle/Test/KernelTestCase.php:67
/home/runner/work/ux/ux/src/Icons/vendor/zenstruck/console-test/src/InteractsWithConsole.php:40
/home/runner/work/ux/ux/src/Icons/vendor/zenstruck/console-test/src/InteractsWithConsole.php:27
/home/runner/work/ux/ux/src/Icons/tests/Integration/Command/ImportIconCommandTest.php:46
```

Commits
-------

680da0c [FrameworkBundle] Ensure `Email` class exists before using it

Author: fabpot

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php

@@ -1067,7 +1067,7 @@ private function addValidationSection(ArrayNodeDefinition $rootNode, callable $e
                             ->validate()->castToArray()->end()
                         ->end()
                         ->scalarNode('translation_domain')->defaultValue('validators')->end()
-                        ->enumNode('email_validation_mode')->values(Email::VALIDATION_MODES + ['loose'])->end()
+                        ->enumNode('email_validation_mode')->values((class_exists(Email::class) ? Email::VALIDATION_MODES : ['html5-allow-no-tld', 'html5', 'strict']) + ['loose'])->end()
                         ->arrayNode('mapping')
                             ->addDefaultsIfNotSet()
                             ->fixXmlConfig('path')