fix(contacts): allow address book to be local but not system

[ArtificialOwl]

if set as local system address book, a userId is expected in some place like

server/lib/private/Collaboration/Collaborators/MailPlugin.php

Lines 114 to 134 in 77194d5

	if (isset($contact['isLocalSystemBook'])) {
	if ($this->shareWithGroupOnly) {
	/*
	* Check if the user may share with the user associated with the e-mail of the just found contact
	*/
	$userGroups = $this->groupManager->getUserGroupIds($this->userSession->getUser());
	// ShareWithGroupOnly filtering
	$userGroups = array_diff($userGroups, $this->shareWithGroupOnlyExcludeGroupsList);
	$found = false;
	foreach ($userGroups as $userGroup) {
	if ($this->groupManager->isInGroup($contact['UID'], $userGroup)) {
	$found = true;
	break;
	}
	}
	if (!$found) {
	continue;
	}
	}

This fix allow app like ldap_contacts_backend to using a new configuration key to set itself as a local non-system address book

nextcloud/ldap_contacts_backend#350

[blizzz]

could we find a positive name, that describes what it is? isVirtualAdressbook or something like this?

[ArtificialOwl]

could we find a positive name, that describes what it is? isVirtualAdressbook or something like this?

totally agree; fun fact, I had the exact same name in mind but forgot to force push :D