[OBJECT_CACHE_FLUSH_REQUIRED_WHEN_RELEASED] Remove FlatObjectMetadata custom fieldMetadataIds fk aggregator property (#17438)

# Introduction
Currently refactoring `flatEntity` typing, encountering some tsc errors
due to this fk aggregator custom override
It shall now follow generic pattern leading to be named `fieldIds`

Needs to flush object cache when released

packages/twenty-server/src/modules/workflow/workflow-trigger/automated-trigger/listeners/__tests__/workflow-database-event-trigger.listener.spec.ts

@@ -40,7 +40,7 @@ describe('WorkflowDatabaseEventTriggerListener', () => {
       updatedAt: new Date().toISOString(),
       icon: 'Icon123',
       universalIdentifier: 'test-object-metadata',
-      fieldMetadataIds: [],
+      fieldIds: [],
       indexMetadataIds: [],
       viewIds: [],
       applicationId: null,