Refactor new relation sync (#11711)

In this PR:
- this should fix the sync metadata for new relation system

This goes with the recent PR:
https://github.com/twentyhq/twenty/pull/11725

What we want:
- ONE_TO_MANY relations should have no joinColumn and no onDelete
- MANY_TO_ONE should have both

packages/twenty-server/src/engine/metadata-modules/workspace-migration/factories/relation-column-action.factory.ts

@@ -55,6 +55,12 @@ export class RelationColumnActionFactory extends ColumnActionAbstractFactory<Fie
       return [];
     }
 
+    if (
+      currentFieldMetadata.settings.relationType === RelationType.ONE_TO_MANY
+    ) {
+      return [];
+    }
+
     const currentJoinColumnName = currentFieldMetadata.settings.joinColumnName;
     const alteredJoinColumnName = alteredFieldMetadata.settings.joinColumnName;