add parent mailing group type and remove redundant $options from Option Group Type

Add the Parent Mailing Group Type (and remove unnecessary $options in OptionGroupType)

Civi/FormProcessor/Type/Factory.php

@@ -31,6 +31,7 @@
     $this->addType(new CountryIsoCodeType('CountryIsoCode', E::ts('Country ISO Code')));
     $this->addType(new StateProvinceType('StateProvince', E::ts('State/Province')));
     $this->addType(new MailingGroupType('MailingGroup', E::ts('Mailing Group')));
+    $this->addType(new ParentMailingGroupType('ParentMailingGroup', E::ts('Parent Mailing Group')));
     $this->addType(new ParticipantStatusType('ParticipantStatusType', E::ts('Participant Status')));
     $this->addType(new CampaignType('CampaignType', E::ts('Campaign')));
     $this->addType(new FileType('file', E::ts('File')));