Revert "Refactor visible organisations logic into a class method"

This reverts commit 7af73979b0.

app/models/user.rb

@@ -10,12 +10,6 @@ class User < ApplicationRecord
     Thread.current[:current_user]
   end
 
-  def self.visible_organisations
-    return [] unless current
-
-    current.organisation.child_organisations + [current.organisation]
-  end
-
   # Marked as optional because we validate organisation_id below instead so that
   # the error message is linked to the right field on the form
   belongs_to :organisation, optional: true
@@ -95,10 +89,11 @@ class User < ApplicationRecord
   scope :deactivated, -> { where(active: false) }
   scope :active_status, -> { where(active: true).where.not(last_sign_in_at: nil) }
   scope :visible, lambda {
-    if User.current&.support?
+    current_user = User.current
+    if current_user&.support?
       where(discarded_at: nil)
     else
-      where(discarded_at: nil, organisation: visible_organisations)
+      where(discarded_at: nil, organisation: current_user.organisation.child_organisations + [current_user.organisation])
     end
   }