The `undecorated-classes-with-decorated-fields` migration has been
introduced with 904a2018e0, but misses
logic for decorating derived classes of undecorated classes which use
Angular features. Example scenario:
```ts
export abstract class MyBaseClass {
@Input() someInput = true;
}
export abstract class BaseClassTwo extends MyBaseClass {}
@Component(...)
export class MyButton extends BaseClassTwo {}
```
Both abstract classes would need to be migrated. Previously, the migration
only added `@Directive()` to `MyBaseClass`, but with this change, it
also decorates `BaseClassTwo`.
This is necessary because the Angular Compiler requires `BaseClassTwo` to
have a directive definition when it flattens the directive metadata for
`MyButton` in order to perform type checking. Technically, not decorating
`BaseClassTwo` does not break at runtime.
We basically want to enforce consistent use of `@Directive` to simplify the
mental model. [See the migration guide](https://angular.io/guide/migration-undecorated-classes#migrating-classes-that-use-field-decorators).
Fixes#34376.
PR Close#35339
32eafef6a7