Bug: «General» → «Design» → «Title Prefix» option is wrongly used for the Backend, need to be enabled for the Frontend only (and my fix)

Issues
, ,
2

My fix

The code to be corrected is:

Replace it with the code:

/** @var \Magento\Framework\ObjectManagerInterface $om */
$om = \Magento\Framework\App\ObjectManager::getInstance();
/** @var \Magento\Framework\App\State $state */
$state =  $om->get('Magento\Framework\App\State');
/** @var bool $isAdmin */
$isAdmin = 'adminhtml' === $state->getAreaCode();
$preparedTitle = ($isAdmin ? '' : $this->scopeConfig->getValue(
	'design/head/title_prefix',
	\Magento\Store\Model\ScopeInterface::SCOPE_STORE
)) . ' ' . $title . ' ' . $this->scopeConfig->getValue(
	'design/head/title_suffix',
	\Magento\Store\Model\ScopeInterface::SCOPE_STORE
);

Admin area detection code is from here: Check programmatically whether we are in admin panel