Some fields for dataset types can't be edited (displayName, description)

[pdurbin]

In #11753 I added displayName and description fields for dataset types but they can't be edited via API (and there's no UI).

I didn't implement editing because we have these two commands already...

• https://github.com/IQSS/dataverse/blame/v6.9/src/main/java/edu/harvard/iq/dataverse/engine/command/impl/UpdateDatasetTypeLinksToMetadataBlocksCommand.java
• https://github.com/IQSS/dataverse/blob/v6.9/src/main/java/edu/harvard/iq/dataverse/engine/command/impl/UpdateDatasetTypeAvailableLicensesCommand.java

... but we might want to merge these into a single UpdateDatasetTypeCommand that allows you to edit all the possible fields:

• name
• displayName
• description
• linkedMetadataBlocks
• availableLicenses

I imagine we'd use a PUT to overwrite existing values.