500 error when deleting dataset type by name

[pdurbin]

At https://guides.dataverse.org/en/6.7.1/api/native-api.html#delete-dataset-type we don't say you can delete a dataset type by name but if you try you'll get {} as a response and a 500 error.

Here's the stacktrace (from an unmerged, rebased branch so don't expect line numbers to make sense):

[#|2025-09-19T19:24:06.649+0000|SEVERE|Payara 6.2025.3|edu.harvard.iq.dataverse.api.errorhandlers.ThrowableHandler|_
ThreadID=86;_ThreadName=http-thread-pool::jk-connector(1);_TimeMillis=1758309846649;_LevelValue=1000;|
  _status="ERROR";_code=500;_message="Internal server error. More details available at the server logs.";_incidentId
="b12bec1f-10eb-42ab-be9e-33852a2cc7ae";_interalError="IllegalArgumentException";_requestUrl="https://dev1.dataverse
.org/api/v1/datasets/datasetTypes/tmp";_requestMethod="DELETE"||#]

[#|2025-09-19T19:24:06.652+0000|SEVERE|Payara 6.2025.3|edu.harvard.iq.dataverse.api.errorhandlers.ThrowableHandler|_
ThreadID=86;_ThreadName=http-thread-pool::jk-connector(1);_TimeMillis=1758309846652;_LevelValue=1000;|
  java.lang.IllegalArgumentException: ID must be a number
        at edu.harvard.iq.dataverse.api.Datasets.deleteDatasetType(Datasets.java:5753)

Instead of throwing an IllegalArgumentException at https://github.com/IQSS/dataverse/blob/v6.7.1/src/main/java/edu/harvard/iq/dataverse/api/Datasets.java#L5730 I suppose we should return something like this:

return error(BAD_REQUEST, "ID must be a number.");

Or we could support deleting by name. Either way, I'll give this a 3 (a couple hours).