don't check disabled radio inputs

app/views/shared/_visibility_radios.html.haml

@@ -4,7 +4,7 @@
   - disabled = disallowed || restricted
   .radio{ class: [('disabled' if disabled), ('restricted' if restricted)] }
     = form.label "#{model_method}_#{level}" do
-      = form.radio_button model_method, level, checked: (selected_level == level), disabled: disabled
+      = form.radio_button model_method, level, checked: (selected_level == level && !disabled), disabled: disabled
       = visibility_level_icon(level)
       .option-title
         = visibility_level_label(level)