Common - Remove feature flag (#15371)

To be done in an other PR, move graphql-query-runner handlers in
common-api-query-runner folder (+ renaming + typing improvments)


Fixes : 
- totalCount on findMany (Rest)
- getAllSelectedFields did not handle composite field (Rest)
- issue with endCursor (Rest)
- args processing for updateOne and createOne (Rest + Gql)
- fix findDuplicates (Gql)

packages/twenty-server/src/engine/api/common/types/common-page-info.type.ts

@@ -1,4 +1,4 @@
-import { type PageInfo } from 'src/engine/api/rest/core/interfaces/rest-api-base.handler';
+import { type PageInfo } from 'src/engine/api/rest/core/handlers/rest-api-base.handler';
 
 export type CommonPageInfo = {
   hasNextPage: NonNullable<PageInfo['hasNextPage']>;