rpk: bugfix - filter in list-mount

We should default to filter `all`, otherwise we
won't print any operation unless a filter is
provided.

src/go/rpk/pkg/cli/cluster/storage/cancel-mount.go

@@ -65,7 +65,7 @@ Cancel a mount/unmount operation
 				out.MaybeDie(err, "unable to cancel the mount/unmount operation: %v", err)
 			}
 
-			fmt.Printf("Successfully canceled the operation with ID %v", migrationID)
+			fmt.Printf("Successfully canceled the operation with ID %v\n", migrationID)
 		},
 	}
 	return cmd

src/go/rpk/pkg/cli/cluster/storage/list-mount.go

@@ -80,7 +80,7 @@ Use filter to list only migrations in a specific state
 		},
 	}
 	p.InstallFormatFlag(cmd)
-	cmd.Flags().StringVarP(&filter, "filter", "f", "", "Filter the list of migrations by state. Only valid for text")
+	cmd.Flags().StringVarP(&filter, "filter", "f", "all", "Filter the list of migrations by state. Only valid for text")
 	return cmd
 }
 
@@ -166,9 +166,11 @@ func rpadminTopicsToStringSlice(in []rpadmin.NamespacedOrInboundTopic) (resp []s
 	for _, entry := range in {
 		if entry.Namespace != nil {
 			resp = append(resp, fmt.Sprintf("%s/%s", *entry.Namespace, entry.Topic))
-			continue
+		} else if entry.SourceTopicReference.Topic != "" {
+			resp = append(resp, entry.SourceTopicReference.Topic)
+		} else {
+			resp = append(resp, entry.Topic)
 		}
-		resp = append(resp, entry.Topic)
 	}
 	return
 }

src/go/rpk/pkg/cli/cluster/storage/mount.go

@@ -108,10 +108,11 @@ with my-new-topic as the new topic name
 				id = mg.ID
 			}
 
-			fmt.Printf(`
-Topic mount from Tiered Storage topic %v to your Redpanda Cluster topic %v
-has started with Migration ID %v
-To check the status run 'rpk cluster storage status-mount %d`+"\n", t, alias, id, id)
+			fmt.Printf(`Topic mount from Tiered Storage topic %q to your Redpanda Cluster topic %q
+has started with Migration ID %v.
+
+To check the status run 'rpk cluster storage status-mount %d.
+`, t, alias, id, id)
 		},
 	}
 	cmd.Flags().StringVar(&to, "to", "", "New namespace/topic name for the mounted topic (optional)")

src/go/rpk/pkg/cli/cluster/storage/unmount.go

@@ -86,10 +86,11 @@ Unmount topic 'my-topic' from the cluster in the 'my-namespace'
 				id = mg.ID
 			}
 
-			fmt.Printf(`
-Topic unmounting from your Redpanda Cluster topic %v
-has started with Migration ID %v
-To check the status run 'rpk cluster storage status-mount %d`+"\n", t, id, id)
+			fmt.Printf(`Topic unmounting from your Redpanda Cluster topic %q has started with 
+Migration ID %v.
+
+To check the status run 'rpk cluster storage status-mount %d.
+`, t, id, id)
 		},
 	}
 	return cmd