111731: Fixed scope not correctly resetting to no scope when clicking on "Search all of DSpace" in the search scope selector

src/app/shared/search/search.component.spec.ts

@@ -294,6 +294,7 @@ describe('SearchComponent', () => {
 
     const expectedSearchOptions = Object.assign(paginatedSearchOptions$.value, {
       configuration: 'default',
+      scope: '',
       sort: sortOptionsList[0],
     });
     expect(comp.currentConfiguration$).toBeObservable(cold('b', {

src/app/shared/search/search.component.ts

@@ -356,7 +356,7 @@ export class SearchComponent implements OnDestroy, OnInit {
     }
 
     this.currentScope$ = this.routeService.getQueryParameterValue('scope').pipe(
-      map((routeValue: string) => hasValue(routeValue) ? routeValue : this.scope),
+      map((routeValue: string) => hasValue(routeValue) ? routeValue : this.scope ?? ''),
     );
 
     this.isSidebarCollapsed$ = this.isSidebarCollapsed();