udpate FIDMetric source

Signed-off-by: dongyang0122 <[email protected]>

Author: dongyang0122

generation/maisi/scripts/compute_fid2p5d_ct.py

@@ -79,7 +79,7 @@
 
 from datetime import timedelta
 from pathlib import Path
-from generative.metrics import FIDMetric
+from monai.metrics.fid import FIDMetric
 from monai.transforms import Compose
 
 # ------------------------------------------------------------------------------