xdgshellclient: Add a small delay before calling `updateShowOnScreenEdge` from...

xdgshellclient: Add a small delay before calling `updateShowOnScreenEdge` from `frameGeometryChanged`

On Wayland, frameGeometryChanged is emitted only once after a screen
is rotated and before the panel is moved to any edge, so set a small
delay to get the correct geometry of a screen.

BUG: 448420
2 jobs for !1887 with work/fusionfuture/BUG448420-dont-unhide-the-panel in 12 minutes and 15 seconds (queued for 3 seconds)
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