House Democrats are offering a renovated version of their vetoed trade bill that no longer calls for advance notice to employees of impending plant closings. "The bottom line is that we're going to have a trade bill without a plant-closings provision," House Speaker Jim Wright, D-Texas, said Wednesday. Wright said the labor-backed plant-closings plan, a major target of President Reagan's May 24 veto, would be dropped from the trade bill and repackaged as separate legislation. The House will take up the individually packaged plant-closings plan ahead of the trade bill, possibly as early as next week.