Duplicate dataset creation

[isaak]

If you happen to create a dataset with a name that already exists, it fails with

'Error storing tool compatibility: [object Object]' alert.

and in the log:
[error] Attribute (sp_dataset_id) does not pass the type constraint because: Validation failed for 'Int' with value "undefined" at /home/production/cxgn/local-lib/lib/perl5/x8
breedbase_web | Moose::Object::new('CXGN::Dataset', 'HASH(0x6311171ebef8)') called at /home/production/cxgn/sgn/bin/../lib/SGN/Controller/AJAX/Dataset.pm line 462

But it does not inform the user it is because the dataset name they are using already exists.