[TASK] Removed deprecated method call

ext_tables.php

@@ -56,7 +56,6 @@ $TCA['tt_content']['types']['list']['subtypes_addlist'][$pluginSignature] = 'pi_
 // Define the new doktypes
 /** @var \TYPO3\CMS\Core\Imaging\IconRegistry $iconRegistry */
 $iconRegistry = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Core\Imaging\IconRegistry::class);
-$relativeExtensionPath = \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::extRelPath('sg_news');
 
 ###################################
 ### Define the Category Doktype ###