Fix relation field unknown target object (#13129)

Fixes https://github.com/twentyhq/twenty/issues/12867

Issue:
when you have a variable `toto` which is: `Record<string, MyType>` and
you do toto['xxx'], this will be typed as `MyType` instead of `MyType |
undefined`

Solutions:
- activate `noUncheckedIndexedAccess` check in tsconfig, this is the
preferred solution but will take time to get there (this raises 600+
errors)
- use a Map: cf https://github.com/twentyhq/twenty/pull/13125/files
- set the type to Partial<Record<string, MyType>>. Drawback is that when
you do Object.values(toto), you'll get `Array<MyType | undefined>`.
Hence why we have to filter these behind


<img width="1512" alt="image"
src="https://github.com/user-attachments/assets/d0a0bfed-c441-4e53-84c2-2da98ccbcf50"
/>

packages/twenty-server/src/engine/metadata-modules/object-permission/field-permission/field-permission.service.ts

@@ -13,7 +13,7 @@ import {
   PermissionsExceptionMessage,
 } from 'src/engine/metadata-modules/permissions/permissions.exception';
 import { RoleEntity } from 'src/engine/metadata-modules/role/role.entity';
-import { ObjectMetadataItemWithFieldMaps } from 'src/engine/metadata-modules/types/object-metadata-item-with-field-maps';
+import { ObjectMetadataMaps } from 'src/engine/metadata-modules/types/object-metadata-maps';
 import { WorkspacePermissionsCacheService } from 'src/engine/metadata-modules/workspace-permissions-cache/workspace-permissions-cache.service';
 import { WorkspaceCacheStorageService } from 'src/engine/workspace-cache-storage/workspace-cache-storage.service';
 
@@ -126,7 +126,7 @@ export class FieldPermissionService {
     role,
   }: {
     fieldPermission: UpsertFieldPermissionsInput['fieldPermissions'][0];
-    objectMetadataMapsById: Record<string, ObjectMetadataItemWithFieldMaps>;
+    objectMetadataMapsById: ObjectMetadataMaps['byId'];
     rolesPermissions: ObjectRecordsPermissionsByRoleId;
     role: RoleEntity;
   }) {