Cannot perform delta migration on multiselect attributes.

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### Preconditions
1. Magento 1.9.4.2 to 2.4.1
2. Migration data tool 2.4.1

### Steps to reproduce
1. Create a required multi select attribute in Magento 1 and create products using this attribute.
2. Perform a single data migration.
3. Add more products in Magento 1 and fill this attribute.
4. Perform a delta migration

### Expected result
1. The new values are migrated

### Actual result
1. The new products are created but the value is not set for the multiselect attribute

### Additional notes
While trying to understand why the products didn't have the values I noticed that during the data migration step the values are correctly transferred from the `catalog_product_entity_text` to `catalog_product_entity_varchar` table however this is not hapepning in the delta migration.

On my install, the data for this attribute during the delta migration is filled on `catalog_product_entity_text` table by mistake.

No file or test is named. Start by tracing the delta migration handling for multiselect product attributes and compare its writes to catalog_product_entity_text and catalog_product_entity_varchar; reproduce the migration described in the issue. Done means newly added products retain their multiselect values after delta migration, with values in the expected table.

Written by the indexing model from the issue text.