message: refactor(animations): remove publicApi annotations from triggers
  the buildTrigger function and AnimationTrigger class are annotated
  as publicApi which seems wrong and makes changes to the two
  problematic, so they are being removed here
  see:
  PR Close
diff: @@ -15,17 +15,11 @@ import {AnimationStyleNormalizer} from './style_normalization/animation_style_no
  -/**
  - * @publicApi
  - */
  export function buildTrigger(
  name: string, ast: TriggerAst, normalizer: AnimationStyleNormalizer): AnimationTrigger {
  return new AnimationTrigger(name, ast, normalizer);
  }
  -/**
  - * @publicApi
  - */
  export class AnimationTrigger {
  public transitionFactories: AnimationTransitionFactory[] = [];
  public fallbackTransition: AnimationTransitionFactory;
  