nmcli/connections: don't ask to ask with --ask

This is slightly annoying:

  $ nmcli -a c add type ethernet
  There is 1 optional setting for General settings.

No point in asking if there's just one option. Just ask right away:

  $ nmcli -a c add type ethernet
  Interface name:
56 jobs for lr/ask-mode in 26 minutes and 11 seconds (queued for 5 seconds)