Revert "feat(sleep-screen): add sleep screen orientation setting" (#1877)

Reverts crosspoint-reader/crosspoint-reader#1748

The images in landscape mode are borked.

Cover:
<img width="696" height="1004" alt="image"
src="https://github.com/user-attachments/assets/354950f3-d3db-4c9d-a771-60f0868666d2"
/>

Sleep Screen:
<img width="688" height="1044" alt="image"
src="https://github.com/user-attachments/assets/3d675b55-93c1-4b5f-9e98-10e18e54c53e"
/>

src/CrossPointSettings.h

@@ -153,8 +153,6 @@ class CrossPointSettings {
   uint8_t sleepScreenCoverMode = FIT;
   // Sleep screen cover filter
   uint8_t sleepScreenCoverFilter = NO_FILTER;
-  // Sleep screen orientation
-  uint8_t sleepScreenOrientation = PORTRAIT;
   // Status bar settings (statusBar retained for migration only)
   uint8_t statusBar = FULL;
   uint8_t statusBarChapterPageCount = 1;