Issue Summary

when agents reply to JSM requests via public comments with a drag-and-drop .wav/.mp3 audio file attachment in empty comment, the customer receives the email notification with the error text "Unable to embed resource: [filename].wav of type audio" instead of a downloadable link to the file.

Steps to Reproduce

1. Log into a Jira Service Management project as an agent.
2. Open any JSM request and click Reply to customer.
3. Ensure the comment field is empty (no text typed).
4. Drag and drop an audio file (e.g., .wav or .mp3) into the comment editor.
5. Save/send the comment to the customer.
6. Check the email notification received by the customer, they should get error text "Unable to embed resource: [filename].wav of type audio" instead of a downloadable link to the file.

Expected Results

The email notification should contain a downloadable link or a properly rendered attachment for the audio file.

Actual Results

The attachment fails to render in the email notification. Instead, the customer receives the following error text:
Unable to embed resource: [filename].wav of type audio/x-pn-windows-acm
(or audio/mpeg for .mp3 files).

Workaround

This issue only occurs when the audio file is dragged into a completely empty comment.
To bypass this: Type at least one character or a short sentence in the comment field before dragging and dropping the audio file. This forces the file to render as an inline embedded card, which allows the notification to send correctly.