[TASK] Use correct TYPO3 API to add fields to TYPO3_USER_SETTINGS

In ext:rtehtmlarea $GLOBALS is directly accessed. Use the TYPO3 API
method instead.

Resolves: #72665
Releases: master
Change-Id: Iae079d8d7f7e6f77305fa3d2fedd449c4e45ade0
Reviewed-on: https://review.typo3.org/45853


Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Alexander Opitz <opitz.alexander@googlemail.com>
Tested-by: Alexander Opitz <opitz.alexander@googlemail.com>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>

typo3/sysext/rtehtmlarea/ext_tables.php

@@ -59,5 +59,8 @@ if (TYPO3_MODE === 'BE' && \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::i
             'csh' => 'xEXT_rtehtmlarea_PlainText:behaviour'
         )
     ));
-    $GLOBALS['TYPO3_USER_SETTINGS']['showitem'] .= ',--div--;LLL:EXT:rtehtmlarea/Resources/Private/Language/locallang.xlf:rteSettings,rteWidth,rteHeight,rteResize,rteMaxHeight,rteCleanPasteBehaviour';
+
+    \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addFieldsToUserSettings(
+        '--div--;LLL:EXT:rtehtmlarea/Resources/Private/Language/locallang.xlf:rteSettings,rteWidth,rteHeight,rteResize,rteMaxHeight,rteCleanPasteBehaviour'
+    );
 }