[DSC-2422] fix issue with back button, fix minor issue on version notice for workflow item

Porting of [UXP-420]

Author: francescomauto

src/app/item-page/full/full-item-page.component.ts

@@ -1,6 +1,7 @@
 import {
   AsyncPipe,
   KeyValuePipe,
+  Location,
   SlicePipe,
 } from '@angular/common';
 import {
@@ -110,6 +111,7 @@ export class FullItemPageComponent extends ItemPageComponent implements OnInit,
     protected notifyInfoService: NotifyInfoService,
     @Inject(PLATFORM_ID) protected platformId: string,
     @Inject(APP_CONFIG) private appConfig: AppConfig,
+    private location: Location,
   ) {
     super(route, router, items, authorizationService, responseService, linkHeadService, notifyInfoService, platformId);
   }
@@ -134,7 +136,7 @@ export class FullItemPageComponent extends ItemPageComponent implements OnInit,
    * Navigate back in browser history.
    */
   back() {
-    this.router.navigate(['../'], { relativeTo: this.route });
+    this.location.back();
   }
 
   ngOnDestroy() {

src/app/item-page/versions/notice/item-versions-notice.component.ts

@@ -127,7 +127,7 @@ export class ItemVersionsNoticeComponent implements OnInit {
         startWith(false),
       );
     }
-    this.destinationPage$ = this.latestVersion$.pipe(
+    this.destinationPage$ = this.latestVersion$?.pipe(
       switchMap(version => version.item),
       map(item => this.getItemPage(item.payload)),
     );