[PM-19127] - Nested Traverse Optimization (#14881)

* Draft optimization of getNestedCollectionTree

* Added feature flag to wrap nestedTraverse_vNext. added the old implementation back in for feature flagging.

* Correction from CR

* Copied tests over for the vNext method.

---------

Co-authored-by: Thomas Rittson <trittson@bitwarden.com>

apps/web/src/app/admin-console/organizations/collections/vault.component.ts

@@ -125,7 +125,11 @@ import {
   BulkCollectionsDialogResult,
 } from "./bulk-collections-dialog";
 import { CollectionAccessRestrictedComponent } from "./collection-access-restricted.component";
-import { getNestedCollectionTree, getFlatCollectionTree } from "./utils";
+import {
+  getNestedCollectionTree,
+  getFlatCollectionTree,
+  getNestedCollectionTree_vNext,
+} from "./utils";
 import { VaultFilterModule } from "./vault-filter/vault-filter.module";
 import { VaultHeaderComponent } from "./vault-header/vault-header.component";
 
@@ -420,9 +424,16 @@ export class VaultComponent implements OnInit, OnDestroy {
       }),
     );
 
-    const nestedCollections$ = allCollections$.pipe(
-      map((collections) => getNestedCollectionTree(collections)),
-      shareReplay({ refCount: true, bufferSize: 1 }),
+    const nestedCollections$ = combineLatest([
+      this.allCollectionsWithoutUnassigned$,
+      this.configService.getFeatureFlag$(FeatureFlag.OptimizeNestedTraverseTypescript),
+    ]).pipe(
+      map(
+        ([collections, shouldOptimize]) =>
+          (shouldOptimize
+            ? getNestedCollectionTree_vNext(collections)
+            : getNestedCollectionTree(collections)) as TreeNode<CollectionAdminView>[],
+      ),
     );
 
     const collections$ = combineLatest([