feat(settings): implement IDelegatedSettings for password policy settings

[printminion-co]

Summary

Implements IDelegatedSettings for the password policy admin settings page (OCA\Password_Policy\Settings\Settings), instead of the plain ISettings interface. This allows an administrator to delegate management of the password policy to a non-admin user or group via the admin delegation feature, without granting full admin rights.

• getName() returns the translated section label, Password Policy.
• getAuthorizedAppConfig() returns [] — no app config keys are exposed for direct delegated editing beyond the settings form itself.
• IL10N is added as a promoted constructor parameter for the label; it is autowired, so no DI registration change is needed.
• #[\Override] is set on both new methods, matching the rest of the class.

Companion to nextcloud/bruteforcesettings#1246, which makes the same change for the brute-force IP allowlist settings.

AI disclosure

This change was prepared with AI assistance (Claude Code): the cherry-pick and rebase mechanics onto current master, the #[\Override] consistency fix, and this PR description. The underlying code change and the DCO sign-off are from a human contributor.

Testing

• composer lint — clean
• composer cs:check — clean, 0 of 41 files need fixing
• composer psalm was not run locally: the pinned Psalm requires PHP >= 8.3.16 and the available container has PHP 8.3.6. Note that master already reports a DocblockTypeContradiction at lib/Validator/HIBPValidator.php:54 independently of this change; it is not addressed here.
• composer test:unit was not run locally: the bootstrap needs an installed Nextcloud instance. No existing test touches this settings class.