Finalize records before exporting

[crazy-max]

follow-up docker/actions-toolkit#652 (comment)

We should make sure records are finalized before exporting them similar to history trace:

buildx/commands/history/trace.go

Lines 57 to 70 in 9ba3f77

	// build is complete but no trace yet. try to finalize the trace
	time.Sleep(1 * time.Second) // give some extra time for last parts of trace to be written
	c, err := rec.node.Driver.Client(ctx)
	if err != nil {
	return "", nil, err
	}
	_, err = c.ControlClient().UpdateBuildHistory(ctx, &controlapi.UpdateBuildHistoryRequest{
	Ref: rec.Ref,
	Finalize: true,
	})
	if err != nil {
	return "", nil, err
	}

@tonistiigi I wonder if we should have a Finalize attribute in

buildx/commands/history/utils.go

Lines 116 to 119 in 9ba3f77

	type queryOptions struct {
	CompletedOnly bool
	Filters []string
	}

To share logic for both export and trace in queryRecords?