📱 In-App Notifications Improvements/Follow-Ups

[robin-macpherson]

Description

A "master issue" with a nice collection of improvements to make to the In-App Notification System:

• [ ] Browser Notifications
• [ ] Favicon adjustment when a user has unread notifications (#707 )
• [ ] Add "default action" to <SwipeableElement> - which for notifications will be delete
• [x] Handle deleting Level 1 notifications if all Level 2s are deleted/length === 0
• [ ] Switch "Read" to "Unread" after a notification is marked as read
• [ ] Implicitly mark READ upon clicking into a top-level notification
• [ ] Make clap notification post title clickable
• [ ] Swiping back from level 2 should take you back to level 1
• [ ] Properly sanitize markup in Notifications
• [ ] Check on Deep Linking behaviour/inconsistencies
• [ ] Some comments can produce horizontal scrolling
• [ ] Once isSwiping is true, don't allow vertical scrolling
• [ ] Add new notification type for earning a new badge

This issue can be marked as closed once all are complete ✅