feat(tests): update test configurations and improve mocking setup

apps/backend/test/complex/invite-complex-user.handler.test.ts

@@ -1,6 +1,5 @@
 import { beforeEach, expect, mock, test } from 'bun:test';
 
-import { createInviteComplexUserHandler } from '@/modules/complex/handlers/invite-complex-user.handler';
 import type { InviteComplexUserResponse } from '@repo/api-contract';
 
 const inviteComplexUserMock = mock(async () => undefined as unknown as InviteComplexUserResponse);
@@ -15,6 +14,10 @@ class MockComplexMembersError extends Error {
   }
 }
 
+const { createInviteComplexUserHandler } = await import(
+  '@/modules/complex/handlers/invite-complex-user.handler'
+);
+
 const inviteComplexUserHandler = createInviteComplexUserHandler({
   inviteComplexUser: inviteComplexUserMock,
   ComplexMembersError: MockComplexMembersError,
@@ -59,7 +62,6 @@ function createContext(input: {
 
 beforeEach(() => {
   inviteComplexUserMock.mockReset();
-  mock.clearAllMocks();
 });
 
 test('returns 201 with the service result', async () => {