Update definitions to $defs

This seems to be a breaking change in pydantics json schema export function.

web/src/views/CreateDandisetView/CreateDandisetView.vue

@@ -181,7 +181,7 @@ const descriptionMaxLength: ComputedRef<number> = computed(
  () => store.schema.properties.description.maxLength,
 );
 const dandiLicenses: ComputedRef<LicenseType[]> = computed(
- () => store.schema.definitions.LicenseType.enum,
+ () => store.schema.$defs.LicenseType.enum,
 );
 
 if (!loggedIn()) {