add huber_loss to fix ci, test=develop (#27766)

python/paddle/nn/functional/loss.py

@@ -41,6 +41,7 @@ from ...fluid.layers import teacher_student_sigmoid_loss  #DEFINE_ALIAS
 
 from ...fluid.layers import edit_distance  #DEFINE_ALIAS
 from ...fluid.layers import sampled_softmax_with_cross_entropy  #DEFINE_ALIAS
+from ...fluid.layers import huber_loss
 from ...fluid.layer_helper import LayerHelper
 from ...fluid.framework import in_dygraph_mode
 from ...fluid.framework import _varbase_creator