[backends] Enable auto-rotate for OpenCV backend

Is now disabled in the latest version of OpenCV.
See opencv/opencv#26795 for context.

Fixes failing rotation tests.

Author: Breakthrough

scenedetect/backends/opencv.py

@@ -350,6 +350,7 @@ def _open_capture(self, framerate: Optional[float] = None):
         self._cap = cap
         self._frame_rate = framerate
         self._has_grabbed = False
+        cap.set(cv2.CAP_PROP_ORIENTATION_AUTO, 1.0)  # https://github.com/opencv/opencv/issues/26795
 
 
 # TODO(#168): Support non-monotonic timing for `position`. VFR timecode support is a