Remove registration of Adafactor because it was added to torch 2.5

Author: tibor-reiss

mmengine/optim/optimizer/builder.py

@@ -166,7 +166,6 @@ def register_transformers_optimizers():
     except ImportError:
         pass
     else:
-        OPTIMIZERS.register_module(name='Adafactor', module=Adafactor)
         transformer_optimizers.append('Adafactor')
     return transformer_optimizers