Refactor flat entity maps to be universal oriented (#17665)

# Introduction
In preparation of the workspace agnostic builder, we're migrating
`FlatEntityMaps` to be universal identifier oriented and based
As in the builder context there're won't be any ids at all
Please also note that the FlatEntity is a UniversalFlatEntity superset

From
```ts
import { type SyncableFlatEntity } from 'src/engine/metadata-modules/flat-entity/types/flat-entity-from.type';

export type FlatEntityMaps<T extends SyncableFlatEntity> = {
  byId: Partial<Record<string, T>>;
  idByUniversalIdentifier: Partial<Record<string, string>>;
  universalIdentifiersByApplicationId: Partial<Record<string, string[]>>;
};
```

To
```ts
export type FlatEntityMaps<
  T extends SyncableFlatEntity | UniversalSyncableFlatEntity,
> = {
  byUniversalIdentifier: Partial<Record<string, T>>;
  universalIdentifierById: Partial<Record<string, string>>;
  universalIdentifiersByApplicationId: Partial<Record<string, string[]>>; // this might make more sense to be migrated to universalIdentifiersByApplicationUniversalIdentifier but it's the main topic of this PR
};
```

## Low level maps tools
Had to refactor find | create | delete | replace | find-many | get-sub
tools ( through mutations and or throw equivalent )

packages/twenty-server/src/engine/twenty-orm/utils/get-object-metadata-from-entity-target.util.ts

@@ -2,6 +2,7 @@ import { type EntityTarget, type ObjectLiteral } from 'typeorm';
 
 import { type WorkspaceInternalContext } from 'src/engine/twenty-orm/interfaces/workspace-internal-context.interface';
 
+import { findFlatEntityByIdInFlatEntityMaps } from 'src/engine/metadata-modules/flat-entity/utils/find-flat-entity-by-id-in-flat-entity-maps.util';
 import { type FlatObjectMetadata } from 'src/engine/metadata-modules/flat-object-metadata/types/flat-object-metadata.type';
 import {
   TwentyORMException,
@@ -35,8 +36,10 @@ export const getObjectMetadataFromEntityTarget = <T extends ObjectLiteral>(
     );
   }
 
-  const objectMetadata =
-    internalContext.flatObjectMetadataMaps.byId[objectMetadataId];
+  const objectMetadata = findFlatEntityByIdInFlatEntityMaps({
+    flatEntityId: objectMetadataId,
+    flatEntityMaps: internalContext.flatObjectMetadataMaps,
+  });
 
   if (!objectMetadata) {
     throw new TwentyORMException(