Remove if-else workflow node flag (#17370)

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[] = [
       imagePath: 'https://twenty.com/images/lab/is-junction-relations.png',
     },
   },
-  {
-    key: FeatureFlagKey.IS_IF_ELSE_ENABLED,
-    metadata: {
-      label: 'If/Else Workflow Node',
-      description: 'Enable if/else conditional branching in workflows',
-      imagePath: 'https://twenty.com/images/lab/is-if-else-enabled.png',
-    },
-  },
   {
     key: FeatureFlagKey.IS_ROW_LEVEL_PERMISSION_PREDICATES_ENABLED,
     metadata: {

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

@@ -12,7 +12,6 @@ export enum FeatureFlagKey {
   IS_TIMELINE_ACTIVITY_MIGRATED = 'IS_TIMELINE_ACTIVITY_MIGRATED',
   IS_ROW_LEVEL_PERMISSION_PREDICATES_ENABLED = 'IS_ROW_LEVEL_PERMISSION_PREDICATES_ENABLED',
   IS_JUNCTION_RELATIONS_ENABLED = 'IS_JUNCTION_RELATIONS_ENABLED',
-  IS_IF_ELSE_ENABLED = 'IS_IF_ELSE_ENABLED',
   IS_SSE_DB_EVENTS_ENABLED = 'IS_SSE_DB_EVENTS_ENABLED',
   IS_COMMAND_MENU_ITEM_ENABLED = 'IS_COMMAND_MENU_ITEM_ENABLED',
   IS_FILES_FIELD_ENABLED = 'IS_FILES_FIELD_ENABLED',