Updates to Message, Remove updated_at/mid from echomails/netmails, not used

app/Models/Echomail.php

@@ -19,6 +19,7 @@ final class Echomail extends Model implements Packet
 	use SoftDeletes,MessageAttributes,MsgID,ParseAddresses,QueryCacheableConfig;
 
 	private const LOGKEY = 'ME-';
+	public const UPDATED_AT = NULL;
 	private bool $no_export = FALSE;
 
 	private const kludges = [

app/Models/Netmail.php

@@ -20,6 +20,7 @@ final class Netmail extends Model implements Packet
 	use SoftDeletes,MsgID,MessageAttributes;
 
 	private const LOGKEY = 'MN-';
+	public const UPDATED_AT = NULL;
 	private const PATH_REGEX = '/^([0-9]+:[0-9]+\/[0-9]+(\..*)?)\s+@([0-9.a-zA-Z]+)\s+(.*)$/';
 
 	/**