Make Arel usages compatible with Rails 6.1 changes

What does this MR do?

Rails 6.1 doesn't allow passing ActiveRecord objects to Arel methods. Let's use .id instead, it generates the same query.

The https://github.com/rails/rails/blob/6-1-stable/activerecord/CHANGELOG.md refers to it as:

Deprecate passing an Active Record object to quote/type_cast directly.