Reduce browse definition requests on simple item page (#3701)

* 121561 Reduce the number of browse definition requests on Item pages by reusing the navbar request for all browse indexes

* Fix test issues.

---------

Co-authored-by: Koen Pauwels <koen.pauwels@atmire.com>

src/app/core/shared/hierarchical-browse-definition.model.ts

@@ -1,6 +1,5 @@
 import {
   autoserialize,
-  autoserializeAs,
   deserialize,
   inheritSerialization,
 } from 'cerialize';
@@ -33,9 +32,6 @@ export class HierarchicalBrowseDefinition extends BrowseDefinition {
   @autoserialize
   vocabulary: string;
 
-  @autoserializeAs('metadata')
-  metadataKeys: string[];
-
   get self(): string {
     return this._links.self.href;
   }