Changed camera's Viewport because of LetterBox in Unity.
After building Android, the following warning is displayed every frame in PostProcessing.
2023-12-08 14:17:47.603 24774 24796 Warn Unity When used with builtin render pipeline, Postprocessing package expects to be used on a fullscreen Camera.
Although the code has been commented out, the code will be restored to its original state.
Due to the LetterBox issue, the Viewport could not be kept at 1,0.