Show notification when media is correctly downloaded

• OS: Ubuntu 22.04.2 LTS
• Jami version: Vil­ágfa 202303071340
• What build you are using: Downloaded from Snap

Steps to reproduce

• Can you reproduce the bug: Yes
• Steps:
  1. Send a picture to someone.
  2. Click on "Enregistrer le fichier" from media setting.
• Actual result: Nothing happens.
• Expected result: Jami should display a message like "Successfully downloaded".

Additional information

Kazam_screencast_00001