OZG-400 fix build

goofy-client/libs/user-profile/src/lib/assign-user-profile-button-container/assign-user-profile-button-container.component.ts

@@ -16,7 +16,12 @@ export class AssignUserProfileButtonContainerComponent {
 	constructor(private userProfileService: UserProfileService) { }
 
 	showUserProfileSearch(): void {
-		document.getElementsByClassName('l-scroll-area')[0].scrollTop = 0; // TODO bessere loesung finden
+		this.scrollToTop(); // TODO bessere loesung finden
 		this.userProfileService.showUserProfileSearch();
 	}
+
+	scrollToTop(): void {
+		const elem = document.getElementsByClassName('l-scroll-area')[0];
+		if (elem) elem.scrollTop = 0;
+	}
 }