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/metadata-modules/flat-page-layout-tab/utils/from-destroy-page-layout-tab-input-to-flat-page-layout-tab-or-throw.util.ts

@@ -5,6 +5,7 @@ import {
 } from 'twenty-shared/utils';
 
 import { type FlatPageLayoutTabMaps } from 'src/engine/metadata-modules/flat-page-layout-tab/types/flat-page-layout-tab-maps.type';
+import { findFlatEntityByIdInFlatEntityMaps } from 'src/engine/metadata-modules/flat-entity/utils/find-flat-entity-by-id-in-flat-entity-maps.util';
 import { type FlatPageLayoutTab } from 'src/engine/metadata-modules/flat-page-layout-tab/types/flat-page-layout-tab.type';
 import {
   PageLayoutTabException,
@@ -27,8 +28,12 @@ export const fromDestroyPageLayoutTabInputToFlatPageLayoutTabOrThrow = ({
     ['id'],
   );
 
-  const existingFlatPageLayoutTabToDestroy =
-    flatPageLayoutTabMaps.byId[pageLayoutTabId];
+  const existingFlatPageLayoutTabToDestroy = findFlatEntityByIdInFlatEntityMaps(
+    {
+      flatEntityId: pageLayoutTabId,
+      flatEntityMaps: flatPageLayoutTabMaps,
+    },
+  );
 
   if (!isDefined(existingFlatPageLayoutTabToDestroy)) {
     throw new PageLayoutTabException(

packages/twenty-server/src/engine/metadata-modules/flat-page-layout-tab/utils/from-update-page-layout-tab-input-to-flat-page-layout-tab-to-update-or-throw.util.ts

@@ -5,6 +5,7 @@ import {
 } from 'twenty-shared/utils';
 
 import { FLAT_PAGE_LAYOUT_TAB_EDITABLE_PROPERTIES } from 'src/engine/metadata-modules/flat-page-layout-tab/constants/flat-page-layout-tab-editable-properties.constant';
+import { findFlatEntityByIdInFlatEntityMaps } from 'src/engine/metadata-modules/flat-entity/utils/find-flat-entity-by-id-in-flat-entity-maps.util';
 import { type FlatPageLayoutTabMaps } from 'src/engine/metadata-modules/flat-page-layout-tab/types/flat-page-layout-tab-maps.type';
 import { type FlatPageLayoutTab } from 'src/engine/metadata-modules/flat-page-layout-tab/types/flat-page-layout-tab.type';
 import { type UpdatePageLayoutTabInput } from 'src/engine/metadata-modules/page-layout-tab/dtos/inputs/update-page-layout-tab.input';
@@ -31,8 +32,10 @@ export const fromUpdatePageLayoutTabInputToFlatPageLayoutTabToUpdateOrThrow = ({
     ['id'],
   );
 
-  const existingFlatPageLayoutTabToUpdate =
-    flatPageLayoutTabMaps.byId[pageLayoutTabToUpdateId];
+  const existingFlatPageLayoutTabToUpdate = findFlatEntityByIdInFlatEntityMaps({
+    flatEntityId: pageLayoutTabToUpdateId,
+    flatEntityMaps: flatPageLayoutTabMaps,
+  });
 
   if (!isDefined(existingFlatPageLayoutTabToUpdate)) {
     throw new PageLayoutTabException(

packages/twenty-server/src/engine/metadata-modules/flat-page-layout-tab/utils/reconstruct-flat-page-layout-tab-with-widgets.util.ts

@@ -15,7 +15,9 @@ export const reconstructFlatPageLayoutTabWithWidgets = ({
   tab: FlatPageLayoutTab;
   flatPageLayoutWidgetMaps: FlatPageLayoutWidgetMaps;
 }): FlatPageLayoutTabWithWidgets => {
-  const widgets = Object.values(flatPageLayoutWidgetMaps.byId).filter(
+  const widgets = Object.values(
+    flatPageLayoutWidgetMaps.byUniversalIdentifier,
+  ).filter(
     (widget): widget is FlatPageLayoutWidget =>
       isDefined(widget) &&
       widget.pageLayoutTabId === tab.id &&