Failed to list cluster if there is an error of topology validate

[9547]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

1. `scale-in` the only TiSpark-master in the cluster with `--force`, the scale results in success, and the TiSpark-master was removed from the cluster;
2. want to list clusters with `tiup-cluster list`, results in error.

2. What did you expect to see?

   1. List cluster success, with an error/warning message appended.
   2. Display cluster success, with an error/warning message appended.

3. What did you see instead?

   ** No cluster listed out**

   root@control:/tiup-cluster# tiup-cluster list
   
   Error: there must be a Spark master node if you want to use the TiSpark component
   
   Verbose debug logs has been written to /tiup-cluster/logs/tiup-cluster-debug-2020-11-16-21-52-23.log.

   Display success, no error/warning message appended

   root@control:/tiup-cluster# tiup-cluster display test_scale_core_32471
   Cluster type:    tidb
   Cluster name:    test_scale_core_32471
   Cluster version: v4.0.4
   SSH type:        builtin
   ID                  Role            Host          Ports        OS/Arch       Status  Data Dir                                  Deploy Dir
   --                  ----            ----          -----        -------       ------  --------                                  ----------
   172.19.0.101:9093   alertmanager    172.19.0.101  9093/9094    linux/x86_64  Up      /home/tidb/deploy/alertmanager-9093/data  /home/tidb/deploy/alertmanager-9093
   172.19.0.104:8300   cdc             172.19.0.104  8300         linux/x86_64  Up      -                                         /home/tidb/deploy/cdc-8300
   172.19.0.105:8300   cdc             172.19.0.105  8300         linux/x86_64  Up      -                                         /home/tidb/deploy/cdc-8300
   172.19.0.101:8249   drainer         172.19.0.101  8249         linux/x86_64  Up      /home/tidb/data/drainer-8249/data         /home/tidb/deploy/drainer-8249
   172.19.0.101:3000   grafana         172.19.0.101  3000         linux/x86_64  Up      -                                         /home/tidb/deploy/grafana-3000
   172.19.0.104:2379   pd              172.19.0.104  2379/2380    linux/x86_64  Up|L    /home/tidb/deploy/pd-2379/data            /home/tidb/deploy/pd-2379
   172.19.0.105:2379   pd              172.19.0.105  2379/2380    linux/x86_64  Up|UI   /home/tidb/deploy/pd-2379/data            /home/tidb/deploy/pd-2379
   172.19.0.101:9090   prometheus      172.19.0.101  9090         linux/x86_64  Up      /home/tidb/deploy/prometheus-9090/data    /home/tidb/deploy/prometheus-9090
   172.19.0.104:8250   pump            172.19.0.104  8250         linux/x86_64  Up      /home/tidb/deploy/pump-8250/data          /home/tidb/deploy/pump-8250
   172.19.0.105:8250   pump            172.19.0.105  8250         linux/x86_64  Up      /home/tidb/deploy/pump-8250/data          /home/tidb/deploy/pump-8250
   172.19.0.101:4000   tidb            172.19.0.101  4000/10080   linux/x86_64  Up      -                                         /home/tidb/deploy/tidb-4000
   172.19.0.102:4000   tidb            172.19.0.102  4000/10080   linux/x86_64  Up      -                                         /home/tidb/deploy/tidb-4000
   172.19.0.101:20160  tikv            172.19.0.101  20160/20180  linux/x86_64  Up      /home/tidb/deploy/tikv-20160/data         /home/tidb/deploy/tikv-20160
   172.19.0.104:20160  tikv            172.19.0.104  20160/20180  linux/x86_64  Up      /home/tidb/deploy/tikv-20160/data         /home/tidb/deploy/tikv-20160
   172.19.0.105:20160  tikv            172.19.0.105  20160/20180  linux/x86_64  Up      /home/tidb/deploy/tikv-20160/data         /home/tidb/deploy/tikv-20160
   172.19.0.104:7078   tispark-worker  172.19.0.104  7078/8081    linux/x86_64  Up      -                                         /home/tidb/deploy/tispark-worker-7078
   Total nodes: 16

4. What version of TiUP are you using (tiup --version)?