Issue Summary

Confluence startup process fails when a non-default character encoding is detected in a custom table (created by users or plugins). Some unpredicted cases may significantly spoil SLAs, for instance, as production can only be made after the DB manipulations (which requires some time for investigation and testing). Maybe a system health check for Confluence administrators is an appropriate place for checking custom tables?

Please remove custom tables charset verification from Confluence startup mandatory checks. A warning message within the health check will be beneficial instead of a startup failure.