Which @angular/* package(s) are relevant/related to the feature request?

forms

Description

With the Reactive Forms API, we are able to trigger the validation with updateValueAndValidity.

Some custom validator (especially async ones) are not idempotent: they might be false due to some third party actions between the reactive validation and the form submission.

Currently we have no way to trigger the validation manually.

Proposed solution

Having a dedicated function exposed on FieldState.

Alternatives considered

No idea