[BUG] Firefox can't show default avatar on notification

Description:

For users who have not set an avatar, the notification sent to other users cannot display the avatar.

Both Edge and Firefox have this problem.

Steps to reproduce:

1. Open rocket.chat page in Chrome browser -> login account A
2. Open rocket.chat page in Firefox browser -> login account B
3. Send message from A to B -> The notification displayed with the avatar is faulty
4. Send message from B to A -> Notification displayed with avatar displayed normally

Expected behavior:

Notification displayed with the user's default avatar.

Actual behavior:

Server Setup Information:

• Version of Rocket.Chat Server: 4.6.3 (due for an upgrade soon)
• Operating System: Ubuntu
• Deployment Method: snap
• Number of Running Instances: 1
• DB Replicaset Oplog: Enabled
• NodeJS Version: 14.18.3
• MongoDB Version: 5.0.6

Client Setup Information

• Desktop App or Browser Version: Chrome 102.0.5005.115 (Official Build) (64-bit), Firefox Version 101.0.1 (64-bit)
• Operating System: Ubuntu 20.04.4 LTS 64-bit

Additional context

Relevant logs:

No file or test is identified in the issue. First reproduce the notification flow across Chrome, Firefox, and Edge with users who have and have not set avatars, then trace the notification avatar rendering entry point; done means the default avatar displays correctly in Firefox and Edge.