Xray custom fields are being duplicated during migration from Jira Data Center to Jira Cloud.

Description

When migrating from the Jira Server/DC to the Cloud using the JCMA, the Xray custom fields Revision, End Date, and Start Date are getting duplicated even if they have the same name in both instances before the migration. ** 

How to reproduce

1. Create a Jira Cloud instance
2. Install the Xray Cloud App
3. Review Jira Cloud issues and custom fields, ensuring that the Revision, End, and Start dates match those in the Jira Data Center custom fields.
4. Perform a migration of Xray project from the Jira DC to the Cloud

Actual result/Attachments

• These fields are being duplicated.

Expected result

• The fields should not be duplicated if they share the same names in both instances.