mod_delegation: use clean_xmlns to remove jabber:client namespace from node: for the same reason as in mod_privilege, `jabber:client` namespace is removed with the clean_xmlns method coming from there. Furthermore, the forwarded <iq> stanza use the `jabber:client` xmlns while the stanza may come from a component with e.g. `jabber:component:accept` xmlns, this can lead to inconsistencies between the <iq> stanza and children (like <error> element).

local allowed_presence_types = { probe = true, unavailable = true };

function filter_presence(event)
	local stanza = event.stanza;
	local presence_type = stanza.attr.type;
	if presence_type == nil or allowed_presence_types[presence_type] then
		return;
	end
	return true; -- Drop
end

module:hook("pre-presence/bare", filter_presence, 200); -- Client sending
module:hook("presence/bare", filter_presence, 200); -- Client receiving