Add PageTS configuration to FlexForm elements

ext_localconf.php

$GLOBALS['TYPO3_CONF_VARS']['SYS']['formEngine']['formDataGroup']['flexFormSegment'][\TYPO3\CMS\Backend\Form\FormDataProvider\PageTsConfig::class] = [];
$GLOBALS['TYPO3_CONF_VARS']['SYS']['formEngine']['formDataGroup']['flexFormSegment'][\TYPO3\CMS\Backend\Form\FormDataProvider\PageTsConfigMerged::class] = [
    'depends' => [
        \TYPO3\CMS\Backend\Form\FormDataProvider\PageTsConfig::class,
    ]
];
$GLOBALS['TYPO3_CONF_VARS']['SYS']['formEngine']['formDataGroup']['flexFormSegment'][\TYPO3\CMS\Backend\Form\FormDataProvider\DatabaseRowDefaultValues::class] = [
    'depends' => [
        \TYPO3\CMS\Backend\Form\FormDataProvider\PageTsConfigMerged::class
    ]
];