Restores encoder proj_sizes as per original paper + associated settings

[colon3ltocard]

• in a previous PR I added proj_size as a setting and it was applied to all EPA modules accross the UnetR++ architectures
• I see a slight (0.4) increase in val_loss following this modification, but spectral RMSE are almost identical
• This PR reverts the proj_sizes as per the original implementation and adds dedicated settings for decoder_proj_size (32) and encoder_proj_sizes (64, 64, 64, 32)