Fix LDAPInvalidFilterErrorldap3

LDAPInvalidFilterError: malformed filter raised due to the search filter
'(&(member=CN=Alessio Curri (new),OU=Contractors,OU=ESS
Users,DC=esss,DC=lu,DC=se))'

The brackets must be encoded using escape_filter_chars() to follow
RFC4515.
See https://github.com/cannatag/ldap3/issues/153

JIRA INFRA-550 #action In Progress