SCI32: Fix null references in Robot decoder

Failing to reduce the size of the ScreenItem arrays causes other
parts of the decoder (like RobotDecoder::getFrameSize) to try
reading ScreenItems that were already destroyed and nulled out in
the list. (In SSCI, the screen item count was held in a separate
property instead of being part of the screen item list.)

engines/sci/video/robot_decoder.cpp

@@ -1436,6 +1436,14 @@ void RobotDecoder::doVersion5(const bool shouldSubmitAudio) {
 			_screenItemList[i] = nullptr;
 		}
 	}
+
+	if (screenItemCount < oldScreenItemCount) {
+		_screenItemList.resize(screenItemCount);
+		_screenItemX.resize(screenItemCount);
+		_screenItemY.resize(screenItemCount);
+		_originalScreenItemX.resize(screenItemCount);
+		_originalScreenItemY.resize(screenItemCount);
+	}
 }
 
 void RobotDecoder::createCels5(const byte *rawVideoData, const int16 numCels, const bool usePalette) {