Count unique cameras when starting multi-camera

Previously _expected_cameras was set to len(active_settings), which could overcount when multiple CameraSettings referred to the same physical camera. This change computes a set of unique camera IDs (via get_camera_id) and sets _expected_cameras to its length, ensuring duplicates aren't double-counted.

Author: C-Achard

dlclivegui/services/multi_camera_controller.py

@@ -158,7 +158,9 @@ def start(self, camera_settings: list[CameraSettings]) -> None:
         self._timestamps.clear()
         self._started_cameras.clear()
         self._failed_cameras.clear()
-        self._expected_cameras = len(active_settings)
+
+        unique_ids = {get_camera_id(s) for s in active_settings}
+        self._expected_cameras = len(unique_ids)
 
         for settings in active_settings:
             self._start_camera(settings)