Migration to drop migration: drop correct_work_item_type_id field from work item index

Background

With [Cells 1.0] Default Work Item Types: Ensure wor... (&15272 - closed) we need to make sure values from work_item_types.id are sequential values 1 - 9. This affects the issues table, as we currently have a foreign key issues.work_item_type_id that relies on these values.

The work items index indexes the work_item_type_id field and will need to adjust to accommodate ensuring work item type IDs are constant sequential 1-9 values.

Proposal

• Remove population from the field in Search::Elastic::References::WorkItem
• Remove field from mappings in Search::Elastic::Types::WorkItem
• Add a migration to remove the field from the index. Use the Elastic::MigrationRemoveFieldsHelper
• Update specs as needed