placementtracker: fix quick tiled windows not being restored correctly

Xaver Huglrequested to merge
work/zamundaaa/cherry-pick into Plasma/6.0

There were two problems:

  1. Workspace interacted with the tile mode of windows before inhibiting the placement tracker, so the wrong window state was stored in the placement tracker
  2. Window::setQuickTileMode is unintuitive and has some undesired side effects, meant to handle quick tiling with keyboard shortcuts and by dragging the window with a mouse specifically. This commit just works around that by un-setting the tile mode first

BUG: 461886

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