feat(core): undecorated-classes migration should handle derived abstract classes (#35339)

In version 10, undecorated base classes that use Angular features need
to be decorated explicitly with `@Directive()`. Additionally, derived
classes of abstract directives need to be decorated.

The migration already handles this for undecorated classes that are
not explicitly decorated, but since in V9, abstract directives can be
used, we also need to handle this for explicitly decorated abstract
directives. e.g.

```
@Directive()
export class Base {...}

// needs to be decorated by migration when updating from v9 to v10
export class Wrapped extends Base {}

@Component(...)
export class Cmp extends Wrapped {}
```

PR Close #35339

packages/core/schematics/test/undecorated_classes_with_decorated_fields_migration_spec.ts

@@ -259,6 +259,39 @@ describe('Undecorated classes with decorated fields migration', () => {
     expect(fileContent).toMatch(/}\s+export class MyCompWrapped/);
   });
 
+  it('should add @Directive to derived undecorated classes of abstract directives', async() => {
+    writeFile('/index.ts', `
+      import { Input, Directive, NgModule } from '@angular/core';
+
+      @Directive()
+      export class Base {
+        // ...
+      }
+      
+      export class DerivedA extends Base {}
+      export class DerivedB extends DerivedA {}
+      export class DerivedC extends DerivedB {}
+      
+      @Directive({selector: 'my-comp'})
+      export class MyComp extends DerivedC {}
+      
+      export class MyCompWrapped extends MyComp {}
+      
+      @NgModule({declarations: [MyComp, MyCompWrapped]})
+      export class AppModule {} 
+    `);
+
+    await runMigration();
+    const fileContent = tree.readContent('/index.ts');
+    expect(fileContent).toContain(`import { Input, Directive, NgModule } from '@angular/core';`);
+    expect(fileContent).toMatch(/core';\s+@Directive\(\)\s+export class Base/);
+    expect(fileContent).toMatch(/@Directive\(\)\s+export class DerivedA/);
+    expect(fileContent).toMatch(/@Directive\(\)\s+export class DerivedB/);
+    expect(fileContent).toMatch(/@Directive\(\)\s+export class DerivedC/);
+    expect(fileContent).toMatch(/}\s+@Directive\(\{selector: 'my-comp'}\)\s+export class MyComp/);
+    expect(fileContent).toMatch(/}\s+export class MyCompWrapped/);
+  });
+
   function writeFile(filePath: string, contents: string) {
     host.sync.write(normalize(filePath), virtualFs.stringToFileBuffer(contents));
   }