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/api/utils/__tests__/compute-cursor-arg-filter.utils.spec.ts

@@ -58,17 +58,17 @@ describe('computeCursorArgFilter', () => {
   const buildFlatFieldMetadataMaps = (
     fields: FlatFieldMetadata[],
   ): FlatEntityMaps<FlatFieldMetadata> => ({
-    byId: fields.reduce(
+    byUniversalIdentifier: fields.reduce(
       (acc, field) => {
-        acc[field.id] = field;
+        acc[field.universalIdentifier] = field;
 
         return acc;
       },
       {} as Record<string, FlatFieldMetadata>,
     ),
-    idByUniversalIdentifier: fields.reduce(
+    universalIdentifierById: fields.reduce(
       (acc, field) => {
-        acc[field.universalIdentifier] = field.id;
+        acc[field.id] = field.universalIdentifier;
 
         return acc;
       },

packages/twenty-server/src/engine/api/utils/validate-and-get-order-by.utils.ts

@@ -15,6 +15,7 @@ import {
   GraphqlQueryRunnerExceptionCode,
 } from 'src/engine/api/graphql/graphql-query-runner/errors/graphql-query-runner.exception';
 import { type FlatEntityMaps } from 'src/engine/metadata-modules/flat-entity/types/flat-entity-maps.type';
+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';
 
 const isOrderByDirection = (value: unknown): value is OrderByDirection => {
@@ -103,7 +104,10 @@ export const countRelationFieldsInOrderBy = (
   return orderBy.filter((orderByItem) => {
     const fieldName = Object.keys(orderByItem)[0];
     const fieldMetadataId = fieldIdByName[fieldName];
-    const fieldMetadata = flatFieldMetadataMaps.byId[fieldMetadataId];
+    const fieldMetadata = findFlatEntityByIdInFlatEntityMaps({
+      flatEntityId: fieldMetadataId,
+      flatEntityMaps: flatFieldMetadataMaps,
+    });
 
     return fieldMetadata?.type === FieldMetadataType.RELATION;
   }).length;