Fix slash commands: Add support for description_localizations

[Tutitoos]

This pull request adds support for description_localizations when handling slash commands in the following methods:

• createCommand
• createGuildCommand
• editCommand
• editGuildCommand
• bulkEditCommands
• bulkEditGuildCommands

Currently, these methods do not properly handle the description_localizations field, which is crucial for providing localized descriptions for slash commands. To resolve this, the following code snippet is added to each affected method:

if (command.descriptionLocalizations !== undefined) {
    command.description_localizations = command.descriptionLocalizations;
}

This ensures that descriptionLocalizations is properly passed to the API, allowing for multilingual support in slash command descriptions.

Changes

• Updated all relevant methods to handle the description_localizations field.
• Improved the support for localized descriptions in slash commands.