Ticket 47872 - Filter AND with only one clause should be optimized
Bug Description: If the filter id of the form "(&(attr=value))" it is not detected
that the filtertest can by bypassed like in "(attr=value)"
Fix Description: Check if an AND filter has only one component and this component is not
another complex filter. To make this work, the check if the filter
attribute is a subtyp also had to be applied earlier
Reviewed by: RichM, thanks
(cherry picked from commit 29316b10f02e7cf7b01fe01f9b82b2088453221b)