Don't show "New notifications" bubble when "Only mentions" is selected and notification type is not a mention

[fhemberger]

Describe the bug A clear and concise description of what the bug is.

• Which site: phanpy.social
• Which instance: all

To Reproduce Steps to reproduce the behavior:

1. Show 'Notifications' column
2. Click on 'Only mentions' filter
3. Wait for like, boost, etc. of your toots
4. "New notifications" is shown

Expected behavior "New notifications" should only be shown for mentions.