Fixes
https://linear.app/chatwoot/issue/CW-6070/argumenterror-ephemeral-is-not-a-valid-file-type-argumenterror
**Problem**
The instagram webhooks containing ephemeral (disappearing) message were
causing ArgumentError exceptions because this attachment type is not
supported and was not in the enum validation.
**Solution**
- Added ephemeral to the unsupported_file_type? filter
- Ephemeral attachments are now silently filtered out before processing,
following the same pattern as existing unsupported types (template,
unsupported_type)
0a17976913