Fix rest metadata version missing (#16536)

## Context

The REST pipeline re-fetches/sets the metadata version later in
RestApiBaseHandler#getObjectMetadata by reading from DB and seeding the
cache if it’s missing. That’s the place that actually needs it and
already handles the “undefined” case.

This also mirror the graphql path that was updated 3 weeks ago

packages/twenty-server/src/engine/middlewares/middleware.service.ts

@@ -106,18 +106,6 @@ export class MiddlewareService {
         )
       : undefined;
 
-    if (metadataVersion === undefined && isDefined(data.workspace)) {
-      await this.flatEntityMapsCacheService.invalidateFlatEntityMaps({
-        workspaceId: data.workspace.id,
-        flatMapsKeys: [
-          'flatObjectMetadataMaps',
-          'flatFieldMetadataMaps',
-          'flatIndexMaps',
-        ],
-      });
-      throw new Error('Metadata cache version not found');
-    }
-
     const dataSourcesMetadata = data.workspace
       ? await this.dataSourceService.getDataSourcesMetadataFromWorkspaceId(
           data.workspace.id,