Add applicationId to syncableEntity and fix syncApp deletion (#15170)

## Context
- All flatEntity should extend SyncableEntity
- SyncableEntity should now have applicationId and application relation
- Fix syncApp deletion, should now properly use migration v2 to delete
syncable entities

packages/twenty-server/src/engine/metadata-modules/flat-agent/types/flat-agent.type.ts

@@ -1,4 +1,5 @@
 import { type AgentEntity } from 'src/engine/metadata-modules/agent/agent.entity';
+import { type FlatEntityFrom } from 'src/engine/metadata-modules/flat-entity/types/flat-entity.type';
 
 export const agentEntityRelationProperties = [
   'workspace',
@@ -11,9 +12,7 @@ export const agentEntityRelationProperties = [
 export type AgentEntityRelationProperties =
   (typeof agentEntityRelationProperties)[number];
 
-export type FlatAgent = Omit<
+export type FlatAgent = FlatEntityFrom<
   AgentEntity,
   AgentEntityRelationProperties | 'createdAt' | 'updatedAt' | 'deletedAt'
-> & {
-  universalIdentifier: string;
-};
+>;