Deleting label custom field adds labels from custom field to labels field

Summary

Deleting a custom field of the label field type adds any labels from the deleted custom field in to the labels field

Environment

• Jira fb3a7a83

Steps to Reproduce

1. Create a label custom field
2. Add field to create screen
3. Create a new issue, adding a label to the custom field that was previously created
4. Delete the custom field that was previously created

Expected Results

Custom field is deleted and nothing is added to existing labels field

Actual Results

Custom field is deleted but any labels that was in the custom field is added to the labels field

Workaround

Remove all labels from custom field prior to deleting label custom field