Remove sse feature flag (#18114)

As title

packages/twenty-server/src/engine/core-modules/feature-flag/constants/public-feature-flag.const.ts

@@ -29,14 +29,6 @@ export const PUBLIC_FEATURE_FLAGS: PublicFeatureFlag[] = [
         'https://twenty.com/images/lab/is-row-level-permission-predicates-enabled.png',
     },
   },
-  {
-    key: FeatureFlagKey.IS_SSE_DB_EVENTS_ENABLED,
-    metadata: {
-      label: 'Real-Time',
-      description: 'See all updates without reloading the page',
-      imagePath: 'https://twenty.com/images/lab/is-real-time-enabled.png',
-    },
-  },
   ...(process.env.CLOUDFLARE_API_KEY
     ? [
         // {

packages/twenty-server/src/engine/core-modules/feature-flag/enums/feature-flag-key.enum.ts

@@ -17,7 +17,6 @@ export enum FeatureFlagKey {
   IS_OTHER_FILE_MIGRATED = 'IS_OTHER_FILE_MIGRATED',
   IS_ROW_LEVEL_PERMISSION_PREDICATES_ENABLED = 'IS_ROW_LEVEL_PERMISSION_PREDICATES_ENABLED',
   IS_JUNCTION_RELATIONS_ENABLED = 'IS_JUNCTION_RELATIONS_ENABLED',
-  IS_SSE_DB_EVENTS_ENABLED = 'IS_SSE_DB_EVENTS_ENABLED',
   IS_COMMAND_MENU_ITEM_ENABLED = 'IS_COMMAND_MENU_ITEM_ENABLED',
   IS_NAVIGATION_MENU_ITEM_ENABLED = 'IS_NAVIGATION_MENU_ITEM_ENABLED',
   IS_DATE_TIME_WHOLE_DAY_FILTER_ENABLED = 'IS_DATE_TIME_WHOLE_DAY_FILTER_ENABLED',