Port all instances of Kauthorized action/shell_command to shell_command

The KAuthorized key to prevent shell access according the documentation
is simply "shell_action" not "action/shellAction" so should use
authorize not authorizeKAction

This appears to have come about as part of a porting bug when going from
KApplication::authorize to KAuthorized in kdelibs3 to kdelibs4.

To currently block shell access a sysadmin currently needs to
have both keys set already, so we can be confident it won't have any
actual compatibility problems.