Make breaking changes to reduce complexity

[cmenon12]

What feature do you want to see added?

Make some breaking changes to simplify the application.

• For Add support for branching to different questions depending on user answers #41, TBC:
  • Add next_question_value to all questions in all prototypes pointing to the next question number, except for branching_choice questions.
  • Add validation to ensure that all new prototypes have this.
  • Remove handling for if questions that are not branching_choice do not have next_question_value.
• For Remove the chat history property from prototypes #73:
  • Add the prompt property with the userMessage from the last item in the chatHistory array.
  • Remove the chatHistory array.
  • If the prompt is "Form generated from JSON input", make it undefined. Editing the JSON does not involve a prompt.
• Add show_progress_indicators property to all existing prototypes with the value true, this was added in Add Markdown support, add optional detailed descriptions to question pages #80

Why do you want this feature? Does it solve a problem?

Some values are optional in the schemas because they don't exist in older versions - maintaining this inconsistency is not ideal, and will increase complexity over time.

How should the feature be implemented?

Documents in the MongoDB database will need to be migrated to the new structure, ideally with ts-migrate-mongoose (or similar). The process for this needs to be well-documented in the README and highlighted in the next release.

Additional context (if applicable)

No response