build: enable bundle_dts for forms package (#28854)

This PR also changes the name of NgNoValidate` to `ɵNgNoValidate`. This is because `ngcc` requires the node to retain the original name while dts bundler will rename the node is it's only exported using the aliases.

Example typings files:
```ts
declare class NgNoValidate{
}
export {NgNoValidateas ɵNgNoValidate}
```

will be emitted as
```ts
export declare class ɵNgNoValidate {
}
```

PR Close #28854

packages/forms/src/directives.ts

@@ -80,5 +80,7 @@ export const REACTIVE_DRIVEN_DIRECTIVES: Type<any>[] =
   declarations: SHARED_FORM_DIRECTIVES,
   exports: SHARED_FORM_DIRECTIVES,
 })
-export class InternalFormsSharedModule {
+export class ɵInternalFormsSharedModule {
 }
+
+export {ɵInternalFormsSharedModule as InternalFormsSharedModule};