docstr: Test when inputs to flattening/unflattening use different channels.
code: def test_flatten_batch_to_2d_unflatten_different_feature_dims(self):
      """Test when inputs to flattening/unflattening use different channels."""
      data_in = np.random.uniform(size=(3, 1, 7, 5, 4))
      data_out = np.concatenate([data_in, data_in], axis=-1)
  
      y, unflatten = utils.flatten_batch_to_2d(data_in)
  
      self.assertAllEqual(
          unflatten(tf.concat([y, y], axis=-1)), data_out
      )
  
imports: from absl.testing import parameterized
  import numpy
  from scipy import linalg
  import tensorflow
  from tensorflow_graphics.geometry.convolution import utils
  from tensorflow_graphics.util import test_case
label_desc: Use image node_id 7 for calling the UtilsFlattenBatchTo2dTests obj's underlying member method code with example usage: obj.test_flatten_batch_to_2d_unflatten_different_feature_dims() without return types