rpk topic add-partitions: change ERROR to STATUS

This is more consistent with other commands (and is better if there are
no errors).

Closes redpanda-data#6258.

src/go/rpk/pkg/cli/cmd/topic/add_partitions.go

@@ -53,7 +53,7 @@ func newAddPartitionsCommand(fs afero.Fs) *cobra.Command {
 				}
 			}()
 
-			tw := out.NewTable("topic", "error")
+			tw := out.NewTable("topic", "status")
 			defer tw.Flush()
 
 			for _, resp := range resps.Sorted() {