Fix code review issues: add missing afterEach import and simplify error handling

Co-authored-by: karilint <19990676+karilint@users.noreply.github.com>

frontend/src/components/Reference/ReferenceDetails.tsx

@@ -79,7 +79,7 @@ export const ReferenceDetails = () => {
     try {
       await deleteMutation(parseInt(id!)).unwrap()
     } catch (error) {
-      const message = resolveDeleteErrorMessage(error ?? deleteError)
+      const message = resolveDeleteErrorMessage(error)
       notify(message, 'error')
     }
   }

frontend/tests/references/deleteReference.test.tsx

@@ -1,4 +1,4 @@
-import { beforeEach, describe, expect, it, jest } from '@jest/globals'
+import { afterEach, beforeEach, describe, expect, it, jest } from '@jest/globals'
 import { render, screen, waitFor } from '@testing-library/react'
 import userEvent from '@testing-library/user-event'
 import { MemoryRouter, Route, Routes } from 'react-router-dom'