Actually I was wrong, the problem is not in https://github.com/xwiki-contrib/jira/blob/59c7d51b45ee8ad8fad29b732462b2390fa280dd/jira-config/jira-config-ui/src/main/resources/JIRA/JIRAConfigSheet.xml#L48 but in the JIRAConfigurationMigrator event listener added in JIRA-84.
Thus it's a regression.