When JCMA account's auth token is expired, preflight checks should not fail without explaining the cause

Issue Summary

When the auth tokens have expired for the JCMA/CCMA user, preflight checks fail and the error message supplied does not lead the user or Support to the true problem or the resolution. 

Steps to Reproduce

Unknown how to cause Auth Tokens to expire.

With expired token, attempt to run pre-flight checks in JCMA. 

Expected Results

1. Preflight checks will fail, but 
2. a message will be sent informing the user that authentication failed.

Actual Results

1. Preflight checks do not complete, with an unrelated message about App License checks
2. Migration cannot move forward, and situation Auth failure is obfuscated from user and Support.

The below exception is thrown in the application log file:

2024-02-01 16:28:20,957+0000 pool-92-thread-336 ERROR jiraadmin 988x10977x1 1234567 10.02.03.04,127.0.0.1 /rest/migration/latest/check/a6634d676aece0caf18fd062a4e5608468a2f1b3 [c.a.j.migration.preflight.AsyncCheckExecutor] Pre-flight execution error occurred for check type AppLicenseCheck
java.util.concurrent.ExecutionException: com.atlassian.jira.migration.httpclient.exceptions.UnexpectedStatusCodeException: Received an unexpected status code; expected [200], but received 404:  

Workaround

This error can be triggered by a need to refresh tokens (handled here), or by a need to unlock the instance (handled in MIG-1773).

To refresh your tokens, follow the process here: renew tokens used by JCMA/CCMA

If refreshing the tokens does not resolve the problem, the problem may be caused by an instance lock in the database. Please open an Issue with Migrations Support; this edit must be made on the backend by Support. See MIG-1773, CMA should advise user when target instance is locked for a similar Suggestion relating to that cause.