System processing is inconsistent for similar errors

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

no param should be added after 'tiup dm -v' or 'tiup dm -h ',
but if adding a param behind these two commands, the system processing is not consistent.
for 'tiup dm -v 5' , tiup will ignore param '5', 'tiup dm -v' command will execute successfully
but for 'tiup dm -h 5', will return an error message

2. What did you expect to see?

both two commands return an error

3. What did you see instead?
   [root@localhost ~]# tiup dm -v 5
   Starting component dm: /root/.tiup/components/dm/v1.1.1/tiup-dm -v 5
   tiup version v1.1.1 tiup
   Go Version: go1.13
   Git Branch: release-1.1
   GitHash: 786b6c9
   [root@localhost ~]#
   [root@localhost ~]# tiup dm -h 5
   Error: unknown command "5" for "tiup"
   Verbose debug logs has been written to /root/logs/tiup-cluster-debug-2020-09-11-07-50-38.log.
   Cannot fetch help message from /root/.tiup/components/dm/v1.1.1/tiup-dm failed: exit status 1
   [root@localhost ~]#

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

[root@localhost ~]# tiup dm -v
Starting component dm: /root/.tiup/components/dm/v1.1.2/tiup-dm -v
tiup version v1.1.2 tiup
Go Version: go1.13
Git Branch: release-1.1
GitHash: 7cb85b9-dirty
[root@localhost ~]#

Start by reproducing the two reported entry points, tiup dm -v 5 and tiup dm -h 5, and trace how the tiup dm CLI forwards arguments. Compare the validation paths for -v and -h; done means both commands reject an extra positional argument with an error.