Alllow to delete timesheet_available tasks for non Timesheet admin users
Since #5599 (closed) a timesheet_avaiable task automatically creates a work to enter it's timesheet but create/writing/deleting project works is only available to Timesheet admin users.
It should be possible for a non Timesheet admin user to make the tasks timesheet available, edit it's timesshet start/end date and also delete them.