[MNT] Remove Reshape layer from Deep Learning Clusterers

[aadya940]

Describe the issue

The tf.keras.layers.Reshape was introduced in clustering/deep_learnin to make the input shape of the encoder equal to the output shape of the decoder which is already being tested in test_all_networks.py. So, basically it is unnecessary at the moment.

Suggest a potential alternative/fix

Remove it.