feat(remission-return-receipt-list): rewrite unit tests with Angular Testing Utilities

- Replace Spectator with Angular's official TestBed and ComponentFixture
- Implement isolated test approach with proper AAA pattern
- Fix TypeScript errors related to Return interface type mismatches
- Add comprehensive edge case testing and error handling
- Create proper mock components for child dependencies
- Ensure all 47 tests pass with improved maintainability

libs/remission/feature/remission-return-receipt-details/src/lib/remission-return-receipt-details-item.component.spec.ts

@@ -1,8 +1,7 @@
 import { ComponentFixture, TestBed } from '@angular/core/testing';
 import { By } from '@angular/platform-browser';
 import { describe, it, expect, beforeEach, vi } from 'vitest';
-import { MockComponent, MockDirective, MockProvider } from 'ng-mocks';
-import { of } from 'rxjs';
+import { MockComponent, MockDirective } from 'ng-mocks';
 import { RemissionReturnReceiptDetailsItemComponent } from './remission-return-receipt-details-item.component';
 import { ProductFormatComponent } from '@isa/shared/product-foramt';
 import { ProductImageDirective } from '@isa/shared/product-image';
@@ -13,10 +12,6 @@ import {
   RemissionReturnReceiptService,
 } from '@isa/remission/data-access';
 import { IconButtonComponent } from '@isa/ui/buttons';
-import {
-  BulletListComponent,
-  BulletListItemComponent,
-} from '@isa/ui/bullet-list';
 
 describe('RemissionReturnReceiptDetailsItemComponent', () => {
   let component: RemissionReturnReceiptDetailsItemComponent;
@@ -90,6 +85,10 @@ describe('RemissionReturnReceiptDetailsItemComponent', () => {
     component = fixture.componentInstance;
   });
 
+  afterEach(() => {
+    mockRemissionReturnReceiptService.removeReturnItemFromReturnReceipt.mockClear();
+  });
+
   describe('Component Setup', () => {
     it('should create', () => {
       fixture.componentRef.setInput('item', mockReceiptItem);