Update dataset names from array to dictionary (#9000)

* Migrate dataset names to dictionary

* fix check

* backwards compat

* predict fix

* val fix

* Keep dataset stats behavior identical

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

models/common.py

@@ -449,7 +449,7 @@ class DetectMultiBackend(nn.Module):
 
         # class names
         if 'names' not in locals():
-            names = yaml_load(data)['names'] if data else [f'class{i}' for i in range(999)]
+            names = yaml_load(data)['names'] if data else {i: f'class{i}' for i in range(999)}
         if names[0] == 'n01440764' and len(names) == 1000:  # ImageNet
             names = yaml_load(ROOT / 'data/ImageNet.yaml')['names']  # human-readable names