river: remove bad assertion

The window may be initialized but not yet mapped, in which case
window.map() won't set state to closing just as the comment above
this assert explains.

 river/XdgToplevel.zig | 1 -
 1 file changed, 1 deletion(-)

diff --git a/river/XdgToplevel.zig b/river/XdgToplevel.zig
index 6bc792e..e443884 100644
--- a/river/XdgToplevel.zig
+++ b/river/XdgToplevel.zig
@@ -247,7 +247,6 @@ fn handleDestroy(listener: *wl.Listener(void)) void {
         // not set to .closing by handleUnmap() since handleUnmap() is not
         // called due to the window not being mapped.
         .ready => {
-            assert(!window.initialized);
             assert(!window.mapped);
             window.wm_scheduled.state = .init;
         },