Put workfows behind a feature flag (#6417)

We have recently merged
[#workflow](https://github.com/twentyhq/twenty/pull/6412) but we should
put the workflow standard object behind a feature flag for now

---------

Co-authored-by: bosiraphael <raphael.bosi@gmail.com>

packages/twenty-server/src/engine/metadata-modules/object-metadata/object-metadata.entity.ts

@@ -83,7 +83,7 @@ export class ObjectMetadataEntity implements ObjectMetadataInterface {
   })
   fields: Relation<FieldMetadataEntity[]>;
 
-  @OneToMany(() => FieldMetadataEntity, (field) => field.object, {
+  @OneToMany(() => IndexMetadataEntity, (index) => index.objectMetadata, {
     cascade: true,
   })
   indexes: Relation<IndexMetadataEntity[]>;