appview/models: fix logic issue when converting label record -> label ops

the ordering of ops should be deletes first followed by additions, in
order for ingestions to be idempotent. after every optimistic update the
the DB, we ingest the same record via the firehose. an ordering
difference resulted in certain additions being marked as no-ops when in
reality, it should be an addition followed by a deletion.

Signed-off-by: oppiliappan <[e-mail]>

appview/models/label.go

···
 	}
 
 	var ops []LabelOp
-	for _, o := range record.Add {
+	// deletes first, then additions
+	for _, o := range record.Delete {
 		if o != nil {
 			op := mkOp(o)
-			op.Operation = LabelOperationAdd
+			op.Operation = LabelOperationDel
 			ops = append(ops, op)
 		}
 	}
-	for _, o := range record.Delete {
+	for _, o := range record.Add {
 		if o != nil {
 			op := mkOp(o)
-			op.Operation = LabelOperationDel
+			op.Operation = LabelOperationAdd
 			ops = append(ops, op)
 		}
 	}