fix Deprecation Warning on conversion of tuple to scalar

Error:

/home/toby/mobile/teaching/durham/cv/python-examples-cv/./kalman_tracking_live.py:326: DeprecationWarning: Conversion of an array with ndim > 0 to a scalar is deprecated, and will error in future. Ensure you extract a single element from your array before performing this operation. (Deprecated NumPy 1.25.)
  (int(prediction[0] - (0.5 * w)),
/home/toby/mobile/teaching/durham/cv/python-examples-cv/./kalman_tracking_live.py:327: DeprecationWarning: Conversion of an array with ndim > 0 to a scalar is deprecated, and will error in future. Ensure you extract a single element from your array before performing this operation. (Deprecated NumPy 1.25.)
  int(prediction[1] - (0.5 * h))),
/home/toby/mobile/teaching/durham/cv/python-examples-cv/./kalman_tracking_live.py:328: DeprecationWarning: Conversion of an array with ndim > 0 to a scalar is deprecated, and will error in future. Ensure you extract a single element from your array before performing this operation. (Deprecated NumPy 1.25.)
  (int(prediction[0] + (0.5 * w)),
/home/toby/mobile/teaching/durham/cv/python-examples-cv/./kalman_tracking_live.py:329: DeprecationWarning: Conversion of an array with ndim > 0 to a scalar is deprecated, and will error in future. Ensure you extract a single element from your array before performing this operation. (Deprecated NumPy 1.25.)
  int(prediction[1] + (0.5 * h))),

Author: tobybreckon

kalman_tracking_live.py

@@ -321,10 +321,10 @@ def nothing(x):
             # draw predicton on image - in GREEN
 
             frame = cv2.rectangle(frame,
-                                  (int(prediction[0] - (0.5 * w)),
-                                   int(prediction[1] - (0.5 * h))),
-                                  (int(prediction[0] + (0.5 * w)),
-                                   int(prediction[1] + (0.5 * h))),
+                                  (int(prediction[0][0] - (0.5 * w)),
+                                   int(prediction[1][0] - (0.5 * h))),
+                                  (int(prediction[0][0] + (0.5 * w)),
+                                   int(prediction[1][0] + (0.5 * h))),
                                   (0,
                                       255,
                                       0),