New option clearCache.system does not show up
With #54991 a new system cache was introduced, along with a new TSconfig property, called
options.clearCache.system. However setting this option to true does not work if the user does not also have either
options.clearCache.all set to true too.
This is because the
\TYPO3\CMS\Backend\Toolbar\ClearCacheToolbarItem does not add the "system" options to the list of values to check for granting access.