Ensure issue trackers data migration doesn't fail with

In !18639 (merged) we started migrating data for issue trackers from properties field of services table to jira_tracker_data and issue_tracker_data (called data field tables later in this issue). While everything went fine for issue_tracker_data on gitlab.com the data were not properly migrated for jira_tracker_data. *_iv values are missing in some cases, mostly for api_url field (#198030 (closed)). Later, a customer reported a problem with issue_tracker_data as well (#198938 (closed))

The problems were fixed by removing the migrated data so that users can use their projects.

The purpose of this issue is to find a fix that will allow us to migrate the data.

Few information:

• we use attr_encrypted gem for encrypting the data
• we have been using data field tables since 12.3
• first problem was reported after the data migration in 12.7
• when we tried to migrate the data manually, it worked fine
• there is an issue suggesting we abandon using attr_encrypted gem
• attr_encrypted issue reporting same error we found: https://github.com/attr-encrypted/attr_encrypted/issues/344