[Angular] Application developer can access type-safe props when implementing Components

[jacobsimionato]

Consider the choice picker implementation for each of the three renderers:

• https://github.com/google/A2UI/blob/main/renderers/angular/src/v0_9/catalog/basic/choice-picker.component.ts
• https://github.com/google/A2UI/blob/main/renderers/lit/src/v0_9/catalogs/basic/components/ChoicePicker.ts
• https://github.com/google/A2UI/blob/main/renderers/react/src/v0_9/catalog/basic/components/ChoicePicker.tsx

In angular, we have:

  displayStyle = computed(() => this.props()['displayStyle']?.value());

While in react, it's like:

          if (props.displayStyle === 'chips') {

It'd be nice of Angular provided a type safe way to access the props, even including deeply nested props etc. This makes it way easier to develop Components. It affects the API, so let's do it as soon as we can.

@ava-cassiopeia @gspencergoog