Centralize metadata relations constant + simplification (#16901)

# Introduction
As we introduced a new grain on relation extraction thanks to low level
`SyncableEntity` and `WorkspaceRelatedEntity` we're able to strictly
typesafe extract metadata entity

The new constant centralizes both many to one and one to many constants
metadata entity constants in a more strictly typesafe way. Remains only
the flatEntityForeignKey aggregator which has to be chosen manually
across all available targeted flat entity ids properties

packages/twenty-server/src/engine/workspace-manager/workspace-migration-v2/services/workspace-migration-build-orchestrator.service.ts

@@ -368,8 +368,6 @@ export class WorkspaceMigrationBuildOrchestratorService {
             buildOptions,
             dependencyOptimisticFlatEntityMaps: {
               flatViewMaps: optimisticAllFlatEntityMaps.flatViewMaps,
-              flatViewFilterGroupMaps:
-                optimisticAllFlatEntityMaps.flatViewFilterGroupMaps,
             },
             workspaceId,
           },
@@ -825,7 +823,10 @@ export class WorkspaceMigrationBuildOrchestratorService {
             from: fromFlatPageLayoutMaps,
             to: toFlatPageLayoutMaps,
             buildOptions,
-            dependencyOptimisticFlatEntityMaps: undefined,
+            dependencyOptimisticFlatEntityMaps: {
+              flatObjectMetadataMaps:
+                optimisticAllFlatEntityMaps.flatObjectMetadataMaps,
+            },
             workspaceId,
           },
         );
@@ -898,6 +899,8 @@ export class WorkspaceMigrationBuildOrchestratorService {
             to: toFlatPageLayoutWidgetMaps,
             buildOptions,
             dependencyOptimisticFlatEntityMaps: {
+              flatObjectMetadataMaps:
+                optimisticAllFlatEntityMaps.flatObjectMetadataMaps,
               flatPageLayoutTabMaps:
                 optimisticAllFlatEntityMaps.flatPageLayoutTabMaps,
             },