mod_csi_simple: Explicitly mention iq stanzas

Should be more obvious that all iq stanzas are considered important.
Changes behavior for invalid things in the default namespace.

plugins/mod_csi_simple.lua

@@ -65,8 +65,9 @@ module:hook("csi-is-stanza-important", function (event)
 			end
 		end
 		return false;
+	elseif st_name == "iq" then
+		return true;
 	end
-	return true;
 end, -1);
 
 local function with_timestamp(stanza, from)