fixed with_settings helper so that it works with Setting.self_registration too

before this change using `with_settings: { self_registration: '3' }`
would only mock `Setting.self_registration` correctly but would omit
`Setting.self_registration?`.

spec/support/shared/with_settings.rb

@@ -46,21 +46,15 @@ RSpec.configure do |config|
     if settings.present?
       settings = aggregate_mocked_settings(example, settings)
 
+      allow(Setting).to receive(:[]).and_call_original
+
       settings.each do |k, v|
-        bare, questionmarked = if k.to_s.ends_with?('?')
-                                 [k.to_s[0..-2].to_sym, k]
-                               else
-                                 [k, "#{k}?".to_sym]
-                               end
+        name = k.to_s.sub(/\?\Z/, '') # remove trailing question mark if present to get setting name
 
-        raise "#{k} is not a valid setting" unless Setting.respond_to?(bare)
+        raise "#{k} is not a valid setting" unless Setting.respond_to?(name)
 
-        if Setting.available_settings[bare.to_s] && Setting.available_settings[bare.to_s]['format'] == 'boolean'
-          allow(Setting).to receive(bare).and_return(v)
-          allow(Setting).to receive(questionmarked).and_return(v)
-        else
-          allow(Setting).to receive(k).and_return(v)
-        end
+        allow(Setting).to receive(:[]).with(name).and_return v
+        allow(Setting).to receive(:[]).with(name.to_sym).and_return v
       end
     end
   end