Add End-to-end tests for Delete User functionality

[stefanteixeira]

Description

Add End-to-end tests for Delete User functionality (accessible from https://front.serverest.dev/admin/listarusuarios page).

Ideally, it should perform the following steps:

• Login as Admin user
• Create a dummy user (tip: use the API helper for that 💡 , but remember to point the request to ServeRest Production API)
• Open /admin/listarusuarios
• Click on Delete button for the user you created
• Verify that the user is not visible on the list

Acceptance Criteria

• Tests are properly using Playwright's Locator API (tip: create-product.e2e.test.js for a similar example of Locator usage)
• Tests are added in a proper test file, such as tests/e2e/delete-user.e2e.test.js