[release-18.0] Bypass cobra completion commands so they still function (

#14217) (#14234)

Co-authored-by: vitess-bot[bot] <108069721+vitess-bot[bot]@users.noreply.github.com>

go/cmd/vtctldclient/command/root.go

@@ -141,6 +141,13 @@ func getClientForCommand(cmd *cobra.Command) (vtctldclient.VtctldClient, error)
  }
  }
 
+ // Reserved cobra commands for shell completion that we don't want to fail
+ // here.
+ switch {
+ case cmd.Name() == "__complete", cmd.Parent() != nil && cmd.Parent().Name() == "completion":
+ return nil, nil
+ }
+
  if VtctldClientProtocol != "local" && server == "" {
  return nil, errNoServer
  }