"microovn certificates reissue" does not check for required arguments

[Martin Kalcok]

This is a minor issue, but implementation of `microovn certificates reissue` command [0] does not properly check if at least one argument was supplied and exits with:

Error: accepts 1 arg(s), received 0

Other commands in this scenario defer to running cmd.Help() [1]

[0]https://github.com/canonical/microovn/blob/994eb5e4490274e1a4b5c03725d8ba1905f92c90/microovn/cmd/microovn/certificates_reissue.go#L47
[1] https://github.com/canonical/microovn/blob/59eea7b501d2c7ce3f012e940300bdfd58d9f169/microovn/cmd/microovn/cluster_join.go#L29-L31