Commit 09bab98b1e tried to avoid several workspace changes while in
window construction, but it missed a case:
If we have a window on a secondary monitor with no workspaces enabled
(so it implicitly gets on_all_workspaces = TRUE without requesting it)
and trigger the creation of a second window that has the first as
transient-for, it would first try to set the first workspace than the
transient-for window and then fallback to all/current workspace.
After that commit we only try to set the same workspace than the
transient-for window, but it gets none as neither is on a single workspace,
nor did really request to be on all workspaces.
Fixes crashes when opening transient X11 dialogs in the secondary monitor.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/714
cda9579034