Add int return type to Console Command execute() methods

[rhoerr]

Summary

The three console commands in this module override Symfony\Component\Console\Command\Command::execute() but did not declare the parent's : int return type. Under PHP 8+ signature compatibility checks this produces a fatal error at autoload time:

PHP Fatal error:  Declaration of MageOS\PageBuilderTemplateImportExport\Console\Command\ExportTemplate::execute(...) must be compatible with Symfony\Component\Console\Command\Command::execute(...): int

Fix: add the matching : int return type to all three commands. Each already returns Cli::RETURN_SUCCESS / Cli::RETURN_FAILURE, so no behavior changes.

Files updated:

• Console/Command/ExportTemplate.php
• Console/Command/ImportTemplate.php
• Console/Command/UpdateRemoteTemplateList.php

Test plan

• Module loads on PHP 8.2/8.3/8.4 without fatal error
• bin/magento mage-os:pagebuilder_template:export, :import, and :update_remote_template_list continue to run and return correct exit codes