Enable foreign components to receive and propagate contextual data
across framework boundaries.

Previously, foreign render functions only accepted component properties,
and foreign content projection instructions (`ɵɵforeignContent` /
`ɵɵforeignContentFn`) did not provide any mechanism to expose foreign
framework context to projected Angular embedded views.

With this change:

- Update `ForeignRenderFn` and `ForeignComponent` interfaces to accept
  an optional context parameter and an optional `GET_CONTEXT` symbol
  method.

- Introduce `FOREIGN_CONTEXT` injection token and
  `provideForeignRootContext` helper to configure root context in
  Angular's DI hierarchy.

- Update `ɵɵforeignComponent` instruction to resolve `FOREIGN_CONTEXT`
  from the injection tree and pass it to the foreign component's render
  function.

- Update `ɵɵforeignContent` and `ɵɵforeignContentFn` instructions to
  accept `foreignComponentConstIndex` and wrap embedded view creation
  with a `ForeignContextInjector` when `GET_CONTEXT` is present.

Furthermore, foreign render functions are no longer run inside an
Angular injection context, since it's expected they use the foreign
context support directly.