Remove `translatable_validates`

#### :tophat: User Story
We seem to still have the old `translatable_validates` method hanging around, but we replaced that approach by the `TranslatablePresence` validator. We should remove all references of it.

#### :clipboard: Related documentation
*None*

#### :dart: Acceptance criteria
There's no `translatable_validates` method anymore.

#### :pushpin: Related issues
*None*

