Add `post_process_depth_estimation` for GLPN (#34413)
* add depth postprocessing for GLPN
* remove previous temp fix for glpn tests
* Style changes for GLPN's `post_process_depth_estimation`
Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>
* additional style fix
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Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>
