remove paddle.metrics.cos_sim api (#27569)

* fix api alias

* remove cos_sim

python/paddle/metric/__init__.py

@@ -16,12 +16,11 @@ from .metrics import *
 from . import metrics
 
 from ..fluid.layers.metric_op import accuracy, auc
-from ..fluid.layers.nn import chunk_eval, cos_sim, mean_iou
+from ..fluid.layers.nn import chunk_eval, mean_iou
 
 __all__ = metrics.__all__ + [
     'accuracy',
     'auc',
     'chunk_eval',
-    'cos_sim',
     'mean_iou',
 ]