force use np.uint8 for cv2 lut (#50867)

python/paddle/vision/transforms/functional.py

@@ -440,7 +440,7 @@ def adjust_brightness(img, brightness_factor):
     if _is_pil_image(img):
         return F_pil.adjust_brightness(img, brightness_factor)
     elif _is_numpy_image(img):
-        return F_cv2.adjust_brightness(img, brightness_factor)
+        return F_cv2.adjust_brightness(img.astype(np.uint8), brightness_factor)
     else:
         return F_t.adjust_brightness(img, brightness_factor)