Florian Müllner authored Mar 21, 2020 and Jonas Ådahl committed Mar 24, 2020

Commit cda95790 fixed a corner case when setting the initial workspace
state of transient windows, but it still missed a case:

should_be_on_all_workspaces() returns whether the window should be on all
workspaces according to its properties/placement, but it doesn't take
transient relations into account.

That means in case of nested transients, we can still fail the assert:

 1. on-all-workspaces toplevel
 2. should_be_on_all_workspaces() is TRUE for the first transient's parent,
    as the window from (1) has on_all_workspaces_requested == TRUE
 3. should_be_on_all_workspaces() is FALSE for the second transient's
    parent, as the window from (2) is only on-all-workspace because
    of its parent

We can fix this by either using the state from the root ancestor
instead of the direct transient parent, or by using the parent's
on_all_workspaces_state.

The latter is simpler, so go with that.

GNOME/mutter#1083