Change public profile pages to be disabled for unconfirmed users (#17385)

Fixes #17382

Note that unconfirmed and unapproved accounts can still be searched for
and their (empty) account retrieved using the REST API.

app/controllers/concerns/account_owned_concern.rb

@@ -8,6 +8,7 @@ module AccountOwnedConcern
     before_action :set_account, if: :account_required?
     before_action :check_account_approval, if: :account_required?
     before_action :check_account_suspension, if: :account_required?
+    before_action :check_account_confirmation, if: :account_required?
   end
 
   private
@@ -28,6 +29,10 @@ module AccountOwnedConcern
     not_found if @account.local? && @account.user_pending?
   end
 
+  def check_account_confirmation
+    not_found if @account.local? && !@account.user_confirmed?
+  end
+
   def check_account_suspension
     if @account.suspended_permanently?
       permanent_suspension_response