allow emails without a tld (#2762)

It's perfectly valid to have an email address without a TLD, for instance:

- test@localhost
- test@svc-in-same-k8s-namespace
- test@internal-corp

Fixes #2667

server/src/domain/user/dto/update-user.dto.spec.ts

@@ -0,0 +1,17 @@
+import { plainToInstance } from 'class-transformer';
+import { validate } from 'class-validator';
+import { UpdateUserDto } from './update-user.dto';
+
+describe('update user DTO', () => {
+  it('should allow emails without a tld', async () => {
+    const someEmail = 'test@test';
+
+    const dto = plainToInstance(UpdateUserDto, {
+      email: someEmail,
+      id: '3fe388e4-2078-44d7-b36c-39d9dee3a657',
+    });
+    const errors = await validate(dto);
+    expect(errors).toHaveLength(0);
+    expect(dto.email).toEqual(someEmail);
+  });
+});