Scale is optional input in norms

[zcbenz]

The scale input is allowed to be null, but the frontend APIs require passing it.

cudnn-frontend/include/cudnn_frontend/node/rmsnorm.h

Lines 101 to 102 in 0258951

	CUDNN_FE_VALIDATE_AND_ASSIGN_INPUT_TENSOR(SCALE, Rmsnorm_attributes::input_names::SCALE);
	rmsnorm_operation_builder.setScale(*(tensors.at(SCALE->second->get_uid())));