[Modal Layout Picker] Filter layouts based on supported blocks.

[chipsnyder]

Is your feature request related to a problem? Please describe.

This task is part of the effort to rework the Starter Page Template Picker for new pages. This part of the initiative will focus on modifying the API call /wpcom/v2/sites/{site}/block-layouts to include the supported_blocks
query parameter which will be used to only include layouts that have met a server defined threshold of supported blocks.

Goals

• Create a mechanism that takes exposes the same array of coreBlocks defined in Gutenberg and exposes those to the App.
  • For now, this can be as simple as duplicating the list in coreBlocks to the apps.
  • Ideally this would be a mechanism that would be shared by the block registration as well as the list passed to the apps but that can be separated out to a future enhancement.
• Use this array to modify the API call /wpcom/v2/sites/{site}/block-layouts with the query paramert supported_blocks that was developed as part of Filtering of templates based on the supported blocks #2415

Additional context

Blueprint Flow - iOS

Blueprint Flow - Android