Remove header in notifications
This provides the following advantages:
- Improve accessibility: the contrast of the header move from 1.8 to 11. Additionally, the font size increase making it simpler to read the notifications.
- Improve aesthetics. Aside from being hard to read, the header was visually very heavy. In particular, then the notifications didn't had an icon or buttons and so made the header area bigger than the body of the notifications.
Edited by Carl Schwan