Type of list to render for PromptType.choice prompt.
The style is selected automatically based on the channel and number of options.
Choices are rendered as buttons for channels that support buttons. For other channels they will be rendered as text.
Choices are rendered as an inline list of the form "1. red, 2. green, or 3. blue".
Choices are rendered as a numbered list.
No list is rendered. This is used when the list is included as part of the prompt.