Migrate page layout services (#16443)

Last step of the page layout migration:
- Migrate services
- Write integration tests

packages/twenty-shared/src/utils/compute-diff-between-objects.ts

@@ -30,7 +30,7 @@ type ComputeDiffBetweenObjectsParams<
 };
 
 export const computeDiffBetweenObjects = <
-  T extends { id: string; deletedAt: Date | null },
+  T extends { id: string; deletedAt: string | null },
   K extends { id: string },
 >({
   existingObjects,