simplify types a bit further

Author: yaacovCR

src/execution/buildFieldPlan.ts

@@ -16,8 +16,8 @@ export type DeferUsageSet = ReadonlySet<DeferUsage>;
 
 export interface FieldGroup {
   fields: ReadonlyArray<FieldDetails>;
-  targets: TargetSet;
-  knownTargets: TargetSet;
+  targets?: TargetSet | undefined;
+  knownTargets?: TargetSet | undefined;
 }
 
 export type GroupedFieldSet = Map<string, FieldGroup>;

src/execution/execute.ts

@@ -53,7 +53,7 @@ import type {
   GroupedFieldSet,
   NewGroupedFieldSetDetails,
 } from './buildFieldPlan.js';
-import { buildFieldPlan, NON_DEFERRED_TARGET_SET } from './buildFieldPlan.js';
+import { buildFieldPlan } from './buildFieldPlan.js';
 import type { DeferUsage, FieldDetails } from './collectFields.js';
 import { collectFields, collectSubfields } from './collectFields.js';
 import type {
@@ -958,8 +958,6 @@ function getStreamUsage(
       node: fieldDetails.node,
       deferUsage: undefined,
     })),
-    targets: NON_DEFERRED_TARGET_SET,
-    knownTargets: NON_DEFERRED_TARGET_SET,
   };
 
   const streamUsage = {