Deprecation: #69561 - Replace sprite icons with IconFactory in ContextMenu 

See forge#69561

Description 

The \TYPO3\CMS\Backend\ContextMenu\ContextMenuAction::$class member variable is not used anymore inside Core, therefore it has been marked as deprecated and will be removed with CMS 8.

Affected Installations 

Any installation using third party code, which accesses ContextMenuAction::$class.

Migration 

Remove any reference to ContextMenuAction::$class.