NotificationCard: Performance improvement & code cleanup
NotificationCard: Performance improvement & code cleanup

Compute things that do not change at construction time, rather than on every
render.

Signed-off-by: Gergely Nagy <0efc652ff6792fef6190e3f066133e37a050e52a@gergo.csillger.hu>

algernon/mad-tooter,algernon/mad-tooter