Batch email notifications do not log anything to Outgoing Mail log

Issue Summary

When batched emails are turned on, the logs file atlassian-jira-outgoing-mail.log does not capture or log any entries to troubleshoot and investigate issues even it's enabled to DEBUG.

Steps to Reproduce

• Run Jira instance with batched notifications turned on,
• Enable Outgoing mail log in the Logging and profiling screen,
• Trigger events that result in emails being sent, e.g. user mentions.

Observe that no entries are appended to the atlassian-jira-outgoing-mail.log.

Expected Results

• Customer expects if there is an issue with outgoing email function it should write in the outgoing mail log (at least if it enabled to DEBUG)
• They also expect to have an admin console (UI) for Mails to monitor its flow and enquire past mails history with data (Advanced than Mail queue)

Actual Results

• We do not have any way to troubleshoot the outgoing mail issues in the current design as it is not writing anything even if it's enabled to DEBUG.

Workaround

• You can try using Notification helper to troubleshoot configuration issues (if only some emails are not being sent)
• Enable debug logging for the com.atlassian.jira.plugins.inform package and look into the atlassian-jira.log file