Add LLM-generated Tags to Browse Bills Search

[Mephistic]

Problem

Now that we have LLM-generated tags for bills, we want to allow users to search and filter using those tags in the Browse Bills search in order to improve discoverability of bills relevant to their interests.

Success Criteria

• Implement the design in the linked Figma, adding the following to the Browse Bills Page:
  • A new Instantsearch Facet that filters on Tags
    • This should be a Hierarchical facet, so that the top level is Tag Categories and clicking on an item at the top level will expand the search to show all Tags that fall under that category
• This new content should be toggleable by a new flag in FeatureFlags (something like showLLMFeatures) to control the rollout (the same flag used by the Bill Details page)

Additional Links

• Figma: https://www.figma.com/design/aDuao2uPLjk5FkYwyC5Yrw/Full---LLM-Summaries-%2B-Tags-(2024)?node-id=2853-2550&t=bMak8XSabhhyvHu6-4
• Docs for Hierarchical Menu for Instantsearch React (https://www.algolia.com/doc/api-reference/widgets/hierarchical-menu/react/)
• This is reliant on adding the new tag fields to the back-end - the ticket for that is: