bug #606 [AI Bundle] Fix validation on system prompt translation validation of bundle options (chr-hertel)

This PR was merged into the main branch.

Discussion
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[AI Bundle] Fix validation on system prompt translation validation of bundle options

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| Docs?         | no
| Issues        |
| License       | MIT

Follow up #514

<img width="1260" height="632" alt="image" src="https://github.com/user-attachments/assets/16ae5600-a35f-45db-a39f-39a5adc5ab64" />

Commits
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5be7070 Fix validation on system prompt translation validation of bundle options

Author: OskarStark

src/ai-bundle/config/options.php

@@ -235,7 +235,7 @@
                             ->end()
                             ->validate()
                                 ->ifTrue(function ($v) {
-                                    return \is_array($v) && $v['enabled'] && !interface_exists(TranslatorInterface::class);
+                                    return \is_array($v) && ($v['enabled'] ?? false) && !interface_exists(TranslatorInterface::class);
                                 })
                                 ->thenInvalid('System prompt translation is enabled, but no translator is present. Try running `composer require symfony/translation`.')
                             ->end()