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/database/commands/upgrade-version-command/0-52/0-52-migrate-relations-to-field-metadata.command.ts

@@ -129,8 +129,14 @@ export class MigrateRelationsToFieldMetadataCommand extends ActiveOrSuspendedWor
       ...fieldMetadata,
       settings: {
         relationType,
-        onDelete: relationMetadata.onDeleteAction,
-        joinColumnName: joinColumnFieldMetadata?.name,
+        onDelete:
+          relationType === RelationType.MANY_TO_ONE
+            ? relationMetadata.onDeleteAction
+            : undefined,
+        joinColumnName:
+          relationType === RelationType.MANY_TO_ONE
+            ? joinColumnFieldMetadata?.name
+            : undefined,
       },
       relationTargetFieldMetadataId,
       relationTargetObjectMetadataId,