JIRA issue comment links to other issues are not always updated when migrating

Issue Summary

When migrating projects with JCMA if the migrating project has comments mentioning issues from projects that were not migrated yet, those comments will be converted into text and won't have an actual link to those issues.

Steps to Reproduce

1. Create project A and project B.
2. Create an issue in each project.
3. Comment in the issues and use the issue key from the issue created in the counterpart project. JIRA should turn the issue key into a direct link to the issue.
4. Migrate project A with JCMA.
5. Migrate project B with JCMA in a separate plan.

Expected Results

Both issues should be migrated and the comments on each should have a direct link to the issue.

Actual Results

Only the issue from project B will have a valid link.
Since projet A was migrated when project B didn't exist at the instance the issue-key remains as plain text on the project A comments.

Workaround

It's possible to work around this issue by migrating the two projects in the same plan. But for a large instance, it should be difficult to migrate all projects at once.