Invert visible logic to admin_only?

app/contracts/projects/base_contract.rb

@@ -67,7 +67,7 @@ module Projects
       if user.admin?
         model.available_custom_fields
       else
-        model.available_custom_fields.select(&:visible?)
+        model.available_custom_fields.reject(&:admin_only?)
       end
     end
 

app/models/custom_value.rb

@@ -42,7 +42,7 @@ class CustomValue < ApplicationRecord
            to: :strategy
 
   delegate :editable?,
-           :visible?,
+           :admin_only?,
            :required?,
            :max_length,
            :min_length,

lib/api/v3/utilities/custom_field_injector.rb

@@ -385,7 +385,7 @@ module API
             custom_fields = if current_user.admin?
                               represented.available_custom_fields
                             else
-                              represented.available_custom_fields.select(&:visible?)
+                              represented.available_custom_fields.reject(&:admin_only?)
                             end
 
             custom_field_class(custom_fields)

lib_static/plugins/acts_as_customizable/lib/acts_as_customizable.rb

@@ -168,7 +168,7 @@ module Redmine
         end
 
         def visible_custom_field_values
-          custom_field_values.select(&:visible?)
+          custom_field_values.reject(&:admin_only?)
         end
 
         def custom_value_for(c)