[DSC-2079] Fixes undefined / null stream inside dso-edit-metadata.component.ts

Author: vins01-4science

src/app/dso-shared/dso-edit-metadata/dso-edit-metadata.component.ts

@@ -197,8 +197,7 @@ export class DsoEditMetadataComponent implements OnInit, OnDestroy {
       this.dsoUpdateSubscription = observableCombineLatest([this.route.data, this.route.parent.data]).pipe(
         map(([data, parentData]: [Data, Data]) => Object.assign({}, data, parentData)),
         tap((data: any) => this.initDSO(data.dso.payload)),
-        mergeMap(() => this.retrieveDataService()),
-        withLatestFrom(this.getSecuritySettings()),
+        mergeMap(() => this.retrieveDataService().pipe(withLatestFrom(this.getSecuritySettings()))),
       ).subscribe(([dataService, securitySettings]: [UpdateDataService<DSpaceObject>, MetadataSecurityConfiguration]) => {
         this.securitySettings$.next(securitySettings);
         this.initDataService(dataService);