Description of problem: Trying to delete user (even non admin) I get reponce (manifesting itself in WebUI via red bubble) "Can't delete tha last admin account". Production.log:

Processing by UsersController#destroy as HTML
  Parameters: {"authenticity_token"=>"q9nXX+Vr5C6f38gXvKidlYvtgUHkpBZ+3CNg2P9J/X4=", "id"=>"6-tester"}
Unable to delete the last admin account
Failed to save: Can't delete the last admin account
Redirected to https://example.com/users
Completed 302 Found in 57ms (ActiveRecord: 9.1ms)
Processing by UsersController#index as HTML
  Rendered users/index.html.erb within layouts/application (27.0ms)
  Rendered common/_searchbar.html.erb (3.8ms)
  Rendered home/_user_dropdown.html.erb (1.1ms)
Read fragment views/tabs_and_title_records-3 (0.2ms)
  Rendered home/_topbar.html.erb (2.0ms)
  Rendered layouts/base.html.erb (3.8ms)
Completed 200 OK in 58ms (Views: 34.6ms | ActiveRecord: 5.6ms)
Processing by UsersController#index as HTML
  Rendered users/index.html.erb within layouts/application (22.1ms)
  Rendered common/_searchbar.html.erb (2.9ms)
  Rendered home/_user_dropdown.html.erb (1.1ms)
Read fragment views/tabs_and_title_records-3 (0.2ms)
  Rendered home/_topbar.html.erb (2.0ms)
  Rendered layouts/base.html.erb (3.4ms)
Completed 200 OK in 52ms (Views: 28.4ms | ActiveRecord: 5.3ms)

How reproducible: always/deterministic

Steps to Reproduce:
  1. create user
  2. try deleting user

Actual results:
  "Can't delete tha last admin account",
  user is not delted

Expected results:
  user is deleted