ringmainwindow: fix unwanted reset to welcome view

- Ignore account selection changed signal when account didn't change.
- Do not refresh account selector when account status changed (we used
  to not display disabled accounts in the past but it is not the case
  anymore)

Change-Id: Iddc560f4fc92f44cd87863680a44db360057b6b4
Gitlab: #708
Reviewed-by: Sebastien Blin <sebastien.blin@savoirfairelinux.com>