viewer: Don’t remove widgets using gtk_container_remove()
viewer: Don’t remove widgets using gtk_container_remove()

We can’t remove the DwlTimeline from the container using
gtk_container_remove() because it’s a scrollable widget and hence gets
an implicit scrolling container as a parent, which means it’s not a
direct child of the GtkContainer and hence triggers an assertion
failure.

pwithnall/dunfell,pwithnall/dunfell