120109: Fixed "no elements in sequence" sometimes being thrown on the item bitstream & relationship tabs

(cherry picked from commit decacec)

Author: alexandrevryghem

src/app/item-page/edit-item-page/abstract-item-update/abstract-item-update.component.ts

@@ -16,9 +16,9 @@ import {
   Subscription,
 } from 'rxjs';
 import {
-  first,
   map,
   switchMap,
+  take,
   tap,
 } from 'rxjs/operators';
 
@@ -102,7 +102,7 @@ export class AbstractItemUpdateComponent extends AbstractTrackableComponent impl
     super.ngOnInit();
 
     this.discardTimeOut = environment.item.edit.undoTimeout;
-    this.hasChanges().pipe(first()).subscribe((hasChanges) => {
+    this.hasChanges().pipe(take(1)).subscribe((hasChanges) => {
       if (!hasChanges) {
         this.initializeOriginalFields();
       } else {
@@ -187,7 +187,7 @@ export class AbstractItemUpdateComponent extends AbstractTrackableComponent impl
    */
   private checkLastModified() {
     const currentVersion = this.item.lastModified;
-    this.objectUpdatesService.getLastModified(this.url).pipe(first()).subscribe(
+    this.objectUpdatesService.getLastModified(this.url).pipe(take(1)).subscribe(
       (updateVersion: Date) => {
         if (updateVersion.getDate() !== currentVersion.getDate()) {
           this.notificationsService.warning(this.getNotificationTitle('outdated'), this.getNotificationContent('outdated'));