Refactor `spec/presenters/error_detail_collection_spec.rb`
Refactor `spec/presenters/error_detail_collection_spec.rb`

 - use `instance` with desribed_class to decouple
 - use subjects per method describe
 - use `#method` naming convention
 - use is_expected syntax where possible
 - remove superflous descriptions for brevity and decoupling
 - perform example setup in `before` blocks

ministryofjustice/advocate-defence-payments,ministryofjustice/advocate-defence-payments,ministryofjustice/advocate-defence-payments,ministryofjustice/advocate-defence-payments