Breaking: #71521 - Property userAuthentication removed from CommandController

See Issue #71521

Description

The property $userAuthentication was removed from the Extbase CommandController class and has been migrated to the newly introduced getBackendUserAuthentication() method.

Impact

All command controllers deriving from CommandController with see a fatal error when accessing properties or methods of the removed $userAuthentication property.

Migration

Use the newly introduced getBackendUserAuthentication() method.