FormBuilder does not support nulls in `strictNullChecks` mode

[undsoft]

Is this a regression?

No

Description

1. Enable strictNullChecks.

  constructor(
    private fb: FormBuilder
  ) {}

  protected readonly noBueno = this.fb.group({
    age: [null as string | null],
    //    ^^^^^^^^^^^^^^^^^ TS2322: Type string | null is not assignable to type string
  });

  protected readonly bueno = new FormGroup({
    age: new FormControl(null as string | null),
    // This works.
  });

Another somewhat related issue is that by virtue of extending Angular's form builder, FormBuilder has nonNullable property that returns native Angular implementation and lacks extra functionality from @ngneat/reactive-forms.
This can be confusing when someone is migrating to strictNullChecks and is actively converting form by adding nonNullable to them.

Please provide a link to a minimal reproduction of the bug

No response

Please provide the exception or error you saw

Please provide the environment you discovered this bug in

Anything else?

Angular 19.0.0
Typescript 5.6.2
@ngneat/reactive-forms 5.0.2

Do you want to create a pull request?

No