fix(TU): fix import issues on TU and add user.service TU

src/app.controller.spec.ts

src/auth/auth.controller.spec.ts

src/auth/auth.service.spec.ts

...categories/services/categories-formations.service.spec.ts

src/mailer/mailer.module.ts

src/mailer/mailer.service.spec.ts

src/structures/structures.controller.spec.ts

src/structures/structures.service.spec.ts

src/users/users.controller.spec.ts

src/users/users.service.spec.ts

src/users/users.service.ts