chore(migrate): update migration script for keywordTermUri handling

Added explanatory comments and references to Dataverse 6.3 release notes to clarify migration. Included guidance for manual loading of the keywordTermURI field and revised notices for better user direction.

Author: poikilotherm

modules/dataverse-migrate-db/extra-migrations/V6.2.0.2__migrate_keywordTermUri.sql

@@ -1,4 +1,4 @@
---
+-- See also
 DO
 $$
     DECLARE
@@ -15,8 +15,13 @@ $$
         IF keyword_count > 0 THEN
             RAISE NOTICE '--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---';
             RAISE NOTICE 'Found % keywordValue metadata fields starting with "http"', keyword_count;
+            RAISE NOTICE 'See release notes of Dataverse 6.3 to learn more about migrating these to the keywordTermURI field.';
 
-            IF should_migrate THEN
+            /*
+              To execute this migration, the keywordTermURI metadata field needs to be loaded.
+              So far, we never added metadata fields using a migration. Maybe it's fine to keep it a manual task for now.
+
+           IF should_migrate THEN
                 RAISE NOTICE 'Migrating keywordValue fields with http... to keywordTermUri as requested by -Dmigrate.keywordTermUri';
                 UPDATE datasetfield df
                 SET datasetfieldtype_id = (SELECT id FROM datasetfieldtype WHERE name = 'keywordTermURI')
@@ -31,6 +36,8 @@ $$
             ELSE
                 RAISE NOTICE 'Auto-migrate these into keywordTermUri using `mvn -Dmigrate.keywordTermUri ...` (re-execute migrations)';
             END IF;
+             */
+
             RAISE NOTICE '--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---';
         END IF;
     END