Mark notifications as read when the notification page is displayed.
Based on the discussion in #1065 (closed) we realised the importance of this issue (even for solving the challenges reported in #1065 (closed))
Currently, notifications are marked as read very late. Therefore, they may remain on the notification page for a very long time. Even though they are no longer relevant for a long time (in example the feature release notifications #1065 (closed)).
Therefore, notifications should now also be marked as read when they are displayed on the notification page.
The first time they are displayed, they should still be marked with an orange dot. (Otherwise the dot would never be displayed).
Additionally, the bubble with the number of notifications in the header should only be displayed in the header if there are no unread notifications.
If there is an unread notification, then the bubble should be displayed only in samarbeid orange (without number).