Issue Summary

When selecting to "Migrate users" using the "Migrate your users in advance" option from the JCMA migration dashboard, the pre-migration checks fail to complete correctly.

Steps to Reproduce

1. Select "Migrate users" from the "Migrate your users in advance" recommendation
2. Continue to "Run pre-migration checks"

Expected Results

Pre-migration checks correctly complete.

Actual Results

The data preparation check fails to complete, which blocks the plan from being able to migrate.

The below exception can be found the log file

2025-07-01 12:04:59,326 http-nio-2990-exec-6 ERROR admin 724x162x2 7vf0zl 0:0:0:0:0:0:0:1 /rest/migration/latest/check/b158ecc70cfbe4b58905b8d77c175e6b3c603dea [migration.preflight.rest.PreflightResource]  Preflight lock requires plan to be saved before running preflights - plan name: users_only 

Workaround

Using the normal "Create a migration" option, create a plan but do not select any projects for migration. This will allow for a users and groups only migration.