#608 Change data array into array of entity_ids

[DanCarlyon]

Description

This takes the array of items and extracts the entity_ids for use with the deleteRecords method

Fixed Issues (if relevant)

1. Sales Order Grid - Array to string conversion exception when running Deltas #608: Sales Order Grid - Array to string conversion exception when running Deltas

Manual testing scenarios

1. Run a full Data migration from Magento 1.14.2.3 to Magento 2.2.6
2. Place orders on Magento 1
3. Run a Delta Data migration

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)

[victor-v-rad]

Thank you @DanCarlyon for this pull request. I see $items is always array. So no need to check if it is array or not. I will remove this check after merging pull request if you do not mind.

[DanCarlyon]

@victor-v-rad That's fine by me, thank you :)