do not run paged results against ldap_read ops on PHP7.3+

- previously it was needed as the PHP LDAP handling of paged results was
strange
- but now the read operation would fail, e.g. with extra home dir attribute
set ("Home dir attribute can't be read from LDAP for uid: foobar"

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>