Adapt batches silent padding

[Sukh-P]

Currently we have the adapt_batches configuration setting which allows the _adapt_batches function to modify the batch shape, I have recently through a configuration mistake noticed if you supply a sample that includes NWPs with width and height smaller than the output size that it will pad the NWP data in the samples with 0 values, as per torchvisions center_crop documentation .

This is done silently currently, I think we should either explicitly throw an exception for this case of input size smaller than requested output size as I don't see it as a case we want to support/part of the original intention of this function or at least throw a warning so it's more obvious this is happening, keen to hear thoughts on this, thanks! @peterdudfield @dfulu @AUdaltsova