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/field-operations/files-field-sync/files-field-sync.ts

@@ -19,6 +19,7 @@ import { type WorkspaceInternalContext } from 'src/engine/twenty-orm/interfaces/
 import { STANDARD_ERROR_MESSAGE } from 'src/engine/api/common/common-query-runners/errors/standard-error-message.constant';
 import { getFlatFieldsFromFlatObjectMetadata } from 'src/engine/api/graphql/workspace-schema-builder/utils/get-flat-fields-for-flat-object-metadata.util';
 import { FileEntity } from 'src/engine/core-modules/file/entities/file.entity';
+import { findFlatEntityByIdInFlatEntityMaps } from 'src/engine/metadata-modules/flat-entity/utils/find-flat-entity-by-id-in-flat-entity-maps.util';
 import { type FlatFieldMetadata } from 'src/engine/metadata-modules/flat-field-metadata/types/flat-field-metadata.type';
 import {
   TwentyORMException,
@@ -597,8 +598,10 @@ export class FilesFieldSync {
   }
 
   private getFilesFields(objectMetadataId: string): FlatFieldMetadata[] {
-    const objectMetadata =
-      this.internalContext.flatObjectMetadataMaps.byId[objectMetadataId];
+    const objectMetadata = findFlatEntityByIdInFlatEntityMaps({
+      flatEntityId: objectMetadataId,
+      flatEntityMaps: this.internalContext.flatObjectMetadataMaps,
+    });
 
     if (!objectMetadata) {
       return [];